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Review 2017-2018 - Volume 56

The Obligation to Investigate in Peace Operations:
The Role of Cooperation in Ensuring Effectiveness
VITO TODESCHINI*
Associate Legal Adviser, International Commission of Jurists, MENA Programme

Table of Contents
  1. Introduction
  2. The Obligation to Investigate under Human Rights Law
  3. The Obligation to Investigate under IHL
  4. The Need for Investigative Cooperation
  5. Criminal Jurisdiction and Investigative Cooperation in the UN Model SOFA and MOU
  6. Investigative cooperation: Mapping the Normative Gaps
    1. UN Operations
    2. UN Operations supported by non-UN Forces
    3. NATO Operations
  7. Regulating Investigative Cooperation
    1. An Obligation to Seek Investigative Cooperation?
    2. The Host State
    3. International Organizations
    4. Troop-Contributing States
  8. Conclusion
 1
3
7
11
12
15
15
16
16
18
18
21
22
24
24
I. Introduction

Reports concerning crimes and abuses committed by peace operations personnel deployed in situations of humanitarian crisis often hit the news. Between 2015 and 2016, for instance, several accounts emerged concerning crimes allegedly perpetrated by members of the military contingents of the United Nations (UN) and supporting forces deployed in the Central African Republic (CAR). According to these reports, French soldiers of the Sangaris force were allegedly involved in rape, and sexual exploitation and abuse, 1 while UN peacekeepers from the Democratic Republic of the Congo (DRC) allegedly also committed unlawful killings and enforced disappearances. 2 More generally, reports of sexual exploitation and abuse in the context of UN operations arise on a regular basis, which signals the endemic character of this
* This article was written in a personal capacity; the views expressed cannot be attributed to the International Commission of Jurists. The author wishes to thank Joop Voetelink, Bas van Hoek, Tom Ruys as well as the anonymous reviewers for their useful comments on earlier drafts of the article. All errors are the author’s only. Contact: vito.todeschini@gmail.com. Back
1 New York Times, ‘Peacekeepers Accused of Sexual Abuse in Central African Republic’, 29 January 2016, http://www.nytimes.com/2016/01/30/world/africa/un-peacekeepers-central-african-republic.html. Back
2 New York Times, ‘U.N. Officials Warned That Congolese Soldiers Were Linked to Rape’, 17 March 2016, http://www.nytimes.com/2016/03/18/world/africa/un-officials-warned-that-congolese-soldiers-were-linked-to-rape.html; Human Rights Watch, ‘Central African Republic: Murder by Peacekeepers’, 7 June 2016, https://www.hrw.org/news/2016/06/07/central-african-republic-murder-peacekeepers. Back

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problem despite the wealth of policies and initiatives adopted and developed by various UN Secretaries-General. 3

In these instances, the State to which the military personnel belong ‒ the so-called sending State or troop-contributing State (TCS) 4 ‒ retains both a prerogative and a duty to undertake criminal investigations as prescribed by international law. 5 To investigate effectively, however, such a State also needs to interact with the other actors involved in a peace operation: the host State, the leading international organization, and other TCSs. When a local is killed, for example, the investigating TCS must seek the authorization of the host State in order to perform an autopsy on the victim’s body, to avoid infringing the latter’s sovereignty. Since partial or total non-cooperation on the part of the host State may hamper a TCS’s ability to conduct an investigation effectively, it becomes necessary to understand how the question of cooperation plays out in light of a TCS’s duty to investigate.

The present article will examine the obligation to investigate in the context of peace operations, particularly as deriving from human rights law and international humanitarian law (IHL). It will then proceed to explore the role of investigative cooperation and how the specific agreements applicable in peace operations, especially UN and NATO operations, 6 address this issue. The aim is to map existing normative gaps in this respect, and to propose solutions de lege ferenda based on the obligations stemming from human rights law and IHL in relation to the duty to investigate.

The scope of the enquiry will be limited to acts that under human rights law and/or IHL warrant a criminal investigation: arbitrary deprivations of life, torture and ill-treatment, and enforced disappearances, on the one hand, and war crimes, on the other hand. While focusing on the criminal liability of individuals, the analysis will not deal with State responsibility and the corresponding duty to investigate deriving from failure to plan or review an operation adequately or from institutional/structural deficiencies leading to an unlawful act; 7 nor will it look at administrative investigations or operational reviews into alleged IHL violations not amounting to war crimes. 8

The article will focus on the duty of TCSs to investigate criminal acts allegedly committed by members of their own armed forces deployed abroad. It will in fact be shown that a hallmark of any such deployment, which typically occurs in the context of a peace operation, is that sending States always retain exclusive criminal jurisdiction over their troops. 9 This necessarily places the main focus of the analysis on the legal obligation that TCSs bear with regard to investigations. The obligations of other actors, such as the host State or international organizations, will be considered only to the extent that they interact with a sending State’s duty to investigate.
3 Among others, see A Comprehensive Strategy to Eliminate Future Sexual Exploitation and Abuse in United Nations Peacekeeping Operations (Zeid Report) , UN Doc. A/59/710, 24 March 2005; M. Deschamps, H.B. Jallow & Y. Sooka, Taking Action on Sexual Exploitation and Abuse by Peacekeepers, Report of an Independent Review on Sexual Exploitation and Abuse by International Peacekeeping Forces in the Central African Republic, 17 December 2015. See also the UN dedicated website Preventing Sexual Exploitation and Abuse, https://www.un.org/preventing-sexual-exploitation-and-abuse/. Back
4 The two phrases will be used interchangeably. Back
5 See below Sections II, III and V. Back
6 Other international organizations, notably the African Union (AU) and the European Union (EU), have established and led peace operations. Examples are the AU Mission in Somalia (AMISOM), the AU/UN Hybrid Operation in Darfur (UNAMID), and the EU Naval Force Somalia (Operation Atalanta). For space and time constraints, the present research will focus on UN and NATO operations only; AU, EU or other organizations-led operations will remain outside the scope of this contribution. Back
7 Under human rights law, a State may be required to investigate alleged violations that give rise to State responsibility without engaging individual criminal responsibility. See European Court of Human Rights (ECtHR), McCann et al. v. the United Kingdom, Appl. No. 18984/91, 27 September 1995, §§ 150, 194‒214. Back
8 For analysis of non-criminal types of inquiries, see D. Murray et al. (eds.), Practitioners’ Guide to Human Rights Law in Armed Conflict (New York, Oxford University Press, 2016), pp. 326‒329. Back
9 See below Section V. Back

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For present purposes, the phrase ‘peace operations’ will encompass any operation deployed on the basis of a UN Security Council resolution, without distinguishing between peacekeeping, peace enforcement and enforcement operations. 10 The reason for relying on one single concept is that the categorisation of a peace operation does not affect a TCS’s obligation to investigate, which derives from human rights law and/or IHL and from the specific agreements applicable in peace operations. Moreover, peace operations may or may not take place in the context of an armed conflict. While a Security Council Chapter VII authorisation to use force might raise the probabilities for a peace operation to become involved in an armed conflict, the actual existence of an armed conflict always depends on the facts on the ground. 11 In turn, the applicability of IHL to multinational forces will ensue from their actual involvement in the hostilities. 12 Therefore, a TCS’s duty to investigate under IHL will arise when members of its armed forces deployed in a peace operation are involved in hostilities. 13 Outside armed conflict, the acts of such forces will be governed by human rights law only, 14 as will be the obligation to investigate of TCSs.

The article will first delineate the obligations imposed by human rights law and IHL in relation to investigations into alleged breaches thereof (Sections II‒III). After providing a range of examples regarding how non-cooperation may affect a TCS’s ability to investigate effectively, the analysis will consider the way the specific agreements applicable in UN peace operations regulate investigative cooperation (Sections IV‒V). This will be used to map the normative gaps present in three different types of operations: UN operations; UN operations supported by non-UN forces; and NATO operations (Section VI). The article will then elaborate on the possible impact of human rights law and IHL on investigative cooperation. In particular, it will propose that, as a matter of lex ferenda, such a duty may entail the further obligation to regulate investigative cooperation (Section VII).

II. The Obligation to Investigate under Human Rights Law

Under human rights law, the obligation to investigate is a procedural duty stemming from the right to life, freedom from torture, and the right to liberty. More precisely, an investigation is required into acts, the commission of which gives rise to criminal responsibility, particularly extrajudicial killings, torture and ill-treatment, and enforced disappearances. 15 The obligation to investigate is also acknowledged as a component of a victim’s right to a remedy. 16
10 For an analysis of these concepts, see T.D. Gill & D. Fleck (eds.), The Handbook of the International Law of Military Operations (Oxford, Oxford University Press, 2015, 2nd ed), pp. 4‒5. Back
11 ICTY, Prosecutor v. Tadić, Case IT-94-1, Decision on Jurisdiction, 2 October 1995, § 70: “an armed conflict exists whenever there is a resort to armed force between States or protracted armed violence between governmental authorities and organized armed groups or between such groups within a State”. Back
12 T. Ferraro, ‘The Applicability and Application of International Humanitarian Law to Multinational Forces’, Vol. 95 International Review of the Red Cross 2013, p. 565. Back
13 For a discussion on who becomes a party to the conflict in peace operations ‒ TCSs, the leading international organization, or both ‒ see O. Engdahl, ‘Multinational Peace Operations Forces Involved in Armed Conflict: Who Are the Parties?’, in K.M. Larsen, C. Guldahl Cooper & G. Nystuen (eds.), Searching for a ‘Principle of Humanity’ in International Humanitarian Law (New York, Cambridge University Press, 2013). Back
14 For an analysis of the various legal questions surrounding the applicability of human rights law in peace operations, see K.M. Larsen, The Human Rights Treaty Obligations of Peacekeepers (New York, Cambridge University Press, 2012). Back
15 Updated Set of Principles for the Protection and Promotion of Human Rights through Action to Combat Impunity, UN Doc. E/CN.4/2005/102/Add.1, 8 February 2005, Principle 19; Basic Principles and Guidelines on the Right to a Remedy and Reparation for Victims of Gross Violations of International Human Rights Law and Serious Violations of International Humanitarian Law, UN Doc. A/RES/60/147, 16 December 2005, Principle III, § 4; Inter-American Court of Human Rights (IACtHR), Velasquez Rodriguez v. Honduras, 29 July 1988, Series C No. 4, § 166; Human Rights Committee (HRC), General Comment No. 31: Nature of the General Legal Obligation on States Parties to the Covenant, UN Doc. CCPR/C/21/Rev.1/Add.13, 26 May 2004, § 18; HRC, General Comment No. 36: Art. 6 (Right to Life) , UN Doc. CCPR/C/GC/36, 30 October 2018, § 27; African Commission on Human and Peoples’ Rights (AComHPR), General Comment No. 4: The Right to Redress for Victims of Torture and Other Cruel, Inhuman or Degrading Punishment or Treatment (Art. 5), 21st Extra-Ordinary Session, 23 February‒4 March 2017, §§ 25, 64; UK High Court of Justice, Al-Saadoon et al. v. Secretary of State for Defence, EWHC 715 (Admin), 17 March 2015, §§ 159, 161, 205, 215. Back
16 Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, 10 December 1984, 1465 UNTS 85, Art. 13; International Convention for the Protection of All Persons from Enforced Disappearance, New York, 20 December 2006, 2716 UNTS 3, Art. 12; ECtHR, Aksoy v. Turkey, Appl. No. 21987/93, 18 December 1996, § 98; IACtHR, Blake v. Guatemala, 22 January 1999, Series C No. 48, §§ 62‒63; AComHPR, Principles and Guidelines on the Right to a Fair Trial and Legal Assistance in Africa, Doc. OS(XXX)247, 2003, Principle M, § 7(h), and Principle P, § e; HRC, General Comment 36, supra note 15, § 27. Back

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Human rights bodies find the legal basis of the obligation to investigate in the general duty of States to respect, ensure, and guarantee the rights enshrined in human rights treaties, 17 and in the duty to counter impunity and ensure accountability for human rights violations. 18 A number of human rights instruments, including the Convention against Torture (UNCAT) and the Convention against Enforced Disappearances (UNCED), contain specific provisions enshrining the obligation to investigate. 19 Human rights law requires an investigation to be conducted whenever reasonable grounds exist, or an arguable claim is made, that an act of extra-judicial killing, torture and ill-treatment, or enforced disappearance has been committed. 20 As soon as State authorities are aware of such an allegation, they must initiate an investigation ex officio. There is no need for the victims or their next of kin to file a formal complaint. 21

A State must fulfil its obligation to investigate even in extraterritorial contexts, whenever there is an exercise of jurisdiction in accordance with relevant human rights treaties. This point is especially relevant in respect of peace operations, which by definition take place outside a TCS’s territory. In general, all human rights bodies have acknowledged that human rights law applies extraterritorially in respect of territories or individuals under the de jure or de facto authority and control of a State. 22 Human rights bodies and domestic courts have specifically considered the application of human rights treaties in relation to peace operations. 23 With particular regard to the obligation to investigate, the European Court of Human Rights (ECtHR)
17 ECtHR, McCann, supra note 7, § 161; AComHPR, Sudan Human Rights et al. v. Sudan, Communications 279/03 and 296/05, 45th Ordinary Session, May 2009, § 147, 153; IACtHR, González et al. (“Cotton Field”) v. Mexico, 16 November 2009, Series C No. 205, § 287. Back
18 AComHPR, General Comment No. 3: The Right to Life (Art. 4) , 57th Ordinary Session, 4‒18 November 2015, §§ 7, 17; IACtHR, Blake, supra note 16, § 64. See also Updated Impunity Principles, supra note 15, Principle 19. Back
19 Among others, see UNCAT, Arts. 12–16; UNCED, Arts. 3, 10, 12; Convention on the Rights of Persons with Disabilities, New York, 13 December 2006, 2515 UNTS 3, Art. 16; Principles on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions, UN Doc. E/1989/89, January 1991, Principle 9; Principles on the Effective Investigation and Documentation of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, UN Doc. A/RES/55/89, 4 December 2000, Principle 2; Inter-American Convention to Prevent and Punish Torture, OAS Treaty Series No. 67, 9 December 1985, Art. 8. Back
20 International Commission of Jurists, International Law and the Fight against Impunity (Geneva, 2015), p. 156. Back
21 IACtHR, Valle Jaramillo et al. v. Colombia, 27 November 2008, Series C No. 192, § 101; ECtHR, Al-Skeini et al. v. the United Kingdom, Appl. No. 55721/07, 7 July 2011, §§ 165‒167. Back
22 HRC, Sergio Euben Lopez Burgos v. Uruguay, UN Doc. CCPR/C/OP/1, 29 July 1981, § 12.3; HRC, General Comment 36, supra note 15, § 63; UNCAT Committee, General Comment No. 2: Implementation of Art. 2 by States parties, UN Doc. CAT/C/GC/2, 24 January 2008, § 16; Inter-American Commission on Human Rights (IAComHR), Coard et al. v. United States, Report No. 109/99, 29 September 1999, § 37; IACtHR, The Environment and Human Rights, Advisory Opinion OC-23/17, 15 November 2017, Series A No. 23, §§ 71‒82; AComHPR, General Comment 3, supra note 18, § 14; ECtHR, Loizidou v. Turkey, Appl. No. 15318/89, 25 March 1995, § 62. See also International Court of Justice (ICJ), Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, ICJ Reports 2004, 136, §§ 108‒111. In the Banković case, the ECtHR ruled out the extraterritorial applicability of the ECHR when a State conducts air operations in foreign territory without exercising control over it; Banković et al. v. Belgium et al. , Appl. No. 52207/99, 12 December 2001, § 75. Such an interpretation excludes that a State be held responsible for violations of the ECHR when it bombs foreign territory in absence of ‘boots on the ground’. The ECtHR has since nuanced this interpretation, at times departing from it and conceding to hold a State to its ECHR’s obligations when using force by distance in extraterritorial contexts; see Pad et al. v. Turkey, Appl. No. 60167/00, 28 June 2007, §§ 54–55; Solomou et al. v. Turkey, Appl. No. 36832/97, 24 June 2008, § 51; Al-Skeini, supra note 21, §§ 133–137. Lacking a clear overruling of the Banković decision, however, the line of reasoning adopted therein is still valid within the ECHR system. Back
23 UNCAT Committee, General Comment 2, supra note 22, § 16; HRC, General Comment 31, supra note 15, § 10; General Comment No. 35: Art. 9 (Liberty and Security of Person) , UN Doc. CCPR/C/GC/35, 16 December 2014, § 65, note 185. See also Larsen, supra note 14, pp. 181‒185. Back

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has considered the obligation to investigate alleged violations of the right to life committed by UK and Dutch soldiers in Iraq, 24 and UK courts have examined the extent to which the UK bears such an obligation in extraterritorial contexts. 25 More generally, the Minnesota Protocol provides that “[t]he duty to investigate applies wherever the State has a duty to respect, protect and/or fulfil the right to life, and in relation to any alleged victims or perpetrators within the territory of a state or otherwise subject to a state’s jurisdiction”. 26 What can be maintained is that the duty to investigate, which is a procedural obligation, follows the duty to respect an individual’s rights. 27 As a consequence, it applies extraterritorially as long as the right to life, the right to be free from torture, and the right to liberty do.

A key principle that informs the obligation to investigate is effectiveness. An investigation is effective when capable of establishing the facts and identifying the perpetrators of an alleged violation. 28 The generally-recognised standards defining the effectiveness of an investigation are thoroughness, promptness, independence, impartiality, transparency and the involvement of the victims. 29 First, investigatory bodies must enquire into alleged violations thoroughly, that is, in a manner that can lead to clarifying the facts and circumstances of an incident and identifying those allegedly responsible for a violation. 30 Second, investigations must be prompt and not unduly delayed in order not to undermine a genuine outcome. 31 Third, investigatory bodies must be independent: there must be no formal or factual hierarchy or connection between investigators and perpetrators. 32 Fourth, investigators must be impartial, i.e. free from preconceived ideas about the facts and the persons involved. 33 Fifth, to the fullest possible extent, a State must permit public scrutiny of the investigatory proceedings and their outcome, ensuring their transparency. 34 Finally, the victims or their next of kin must have the possibility to participate in an investigation, be heard by the competent bodies, and challenge the decision not to prosecute those allegedly responsible. 35 It should be highlighted that the obligation to investigate is an obligation of means and not of result: 36 while investigators must take all reasonable steps to ascertain the truth about the facts, they are not supposed to achieve a specific or predetermined result. In this regard, States are required to act with due diligence. 37
24 ECtHR, Al-Skeini, supra note 21; Jaloud v. the Netherlands, Appl. No. 47708/08, 20 November 2014. Back
25 UK High Court of Justice, Al-Saadoon, supra note 15; UK Court of Appeals, Al-Saadoon et al. v. The Secretary of State for Defence et al. [2016] EWCA Civ 811. Back
26 The Minnesota Protocol on the Investigation of Potentially Unlawful Death (2016), Office of the High Commissioner for Human Rights, New York/Geneva, 2017, § 19. The AComHPR also does not confine the obligation to investigate to a State’s territory; General Comment 3, supra note 18, § 20. Back
27 M. Milanovic, Extraterritorial Application of Human Rights Treaties. Law, Principles, and Policy (Oxford, Oxford University Press, 2011), pp. 216‒217. Back
28 ECtHR, Cangöz et al. v. Turkey, Appl. No. 7469/06, 26 April 2016, § 114. Back
29 HRC, General Comment 36, supra note 15, § 28; AComHPR, General Comment 3, supra note 18, §§ 7, 15. Back
30 ECtHR, Kaya v. Turkey, Appl. No. 158/1996/777/978, 19 February 1998, § 107; IACtHR, Cotton Field, supra note 17, § 300. Back
31 IACtHR, Valle Jaramillo, supra note 21, § 101; UNCAT Committee, General Comment No. 3: Implementation of Art. 14 by States Parties, UN Doc. CAT/C/GC/3, 13 December 2012, § 23. Back
32 IACtHR, Velásquez Rodríguez v. Honduras, 29 July 1988, Series C No. 4, § 180; AComHPR, Amnesty International et al. v. Sudan, Communications 48/90, 50/91, 52/91, 89/93, 26th Ordinary Session, November 1999, § 51. Back
33 IACtHR, Valle Jaramillo, supra note 21, § 101; UNCAT Committee, General Comment 3, supra note 31, § 23. Back
34 IACtHR, Juan Humberto Sánchez v. Honduras, 7 June 2003, Series C No. 99, § 186; AComHPR, Amnesty International, supra note 32, § 51. Back
35 ECtHR, Kaya, supra note 30, § 107; IACtHR, Humberto Sánchez, supra note 34, § 186. Back
36 IACtHR, Valle Jaramillo, supra note 21, § 100; ECtHR, Al-Skeini, supra note 21, §§ 165‒167. Back
37 IACtHR, Osorio Rivera and Family v. Peru², 26 November 2013, Series C No. 274, §§ 181‒182. On the role of due diligence with respect to investigative cooperation, see below Section VII 1. Back

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In situations characterised by difficult security conditions, including armed conflict, 38 a State might be prevented to comply in full with the standards of effectiveness. An exhaustive investigation into an incident may indeed be impracticable due to factual conditions, regardless of a State’s intention. 39 Especially during armed conflict, security conditions may impede basic investigative measures such as accessing the field, gathering evidence, and questioning witnesses. 40 At the same time, the existence of difficult security conditions cannot as such justify the refusal to open an investigation. One thing is recognising that the duty to investigate should be tailored to the circumstances when security conditions so demand; another thing is taking advantage of such a situation in order to circumvent the fulfilment of this obligation. As the UN Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions stated, “[i]t is undeniable that during armed conflicts circumstances will sometimes impede investigation. [...] Regardless of the circumstances, however, investigations must always be conducted as effectively as possible and never be reduced to mere formality”. 41

The ECtHR has endeavoured to strike a balance between the protection of human rights and military needs by taking into account security conditions in the assessment of a State’s compliance with the duty to investigate. 42 The Court affirmed the principle that a State must investigate alleged human rights violations under any circumstances, including armed conflict. At the same time, it acknowledged that effectiveness is to be evaluated in light of what a State may reasonably do in light of the concrete circumstances:
It is clear that where the death to be investigated under Article 2 occurs in circumstances of generalised violence, armed conflict or insurgency, obstacles may be placed in the way of investigators and […] concrete constraints may compel the use of less effective measures of investigation or may cause an investigation to be delayed […]. Nonetheless, the obligation under Article 2 to safeguard life entails that, even in difficult security conditions, all reasonable steps must be taken to ensure that an effective, independent investigation is conducted into alleged breaches of the right to life […]. 43
The African Commission on Human and Peoples’ Rights similarly affirmed that “[a]lthough States may face particular practical challenges in achieving accountability in situations of armed conflict, they must undertake all feasible measures of accountability to ensure respect for the right to life”. 44 In the Commission’s view, the concept of accountability encompasses the duty to investigate. 45 In re-affirming the obligation of States to investigate alleged or suspected violation of the right to life in armed conflict, the Human Rights Committee referred to the provisions of the Minnesota Protocol, according to which the standards of effectiveness “[must] be considered in light of both the circumstances and the underlying principles governing international humanitarian law (IHL)”. 46 On the other hand, the Inter-American Court of Human Rights requires States to comply fully with the standards of effectiveness at all times. 47

What is here termed the ‘all reasonable steps/all feasible measures’ test originates from a balancing between practical considerations and effective protection of human rights: a realistic
38 At present, it is widely acknowledged that human rights law continues to apply in armed conflict; ICJ, Wall, supra note 22, § 106. It should be pointed out, however, that human rights norms will be influenced by the concurrent application of IHL; see below Section III. Back
39 A. Cohen & Y. Shany, ‘Beyond the Grave Breaches Regime: The Duty to Investigate Alleged Violations of International Law Governing Armed Conflicts’, Vol. 14 Y.I.H.L. 2011, p. 50. Back
40 M. Schmitt, ‘Investigating Violations of International Law in Armed Conflict’, Vol. 2 Harvard National Security Journal 2011, pp. 54‒55. Back
41 Report of the Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions, UN Doc. E/CN.4/2006/53, 8 March 2006, § 36. See also Minnesota Protocol, supra note 26, § 20. Back
42 ECtHR, Al-Skeini, supra note 21, §§ 161‒162; Isayeva v. Russia, Appl. No. 57950/00, 24 February 2005, § 180. Back
43 ECtHR, Al-Skeini, supra note 21, § 164 (citations omitted; emphasis added). See also Jaloud, supra note 24, § 186. Back
44 AComHPR, General Comment No. 3, supra note 18, § 20 (emphasis added). Back
45 Id. , § 17. Back
46 HRC, General Comment 36, supra note 15, § 64; Minnesota Protocol, supra note 26, § 20. Back
47 IACtHR, Massacres of El Mozote and Nearby Places v. El Salvador, 25 October 2012, Series C No. 252, §§ 242‒249; Santo Domingo Massacre v. Colombia, 30 November 2012, Series C No. 259, §§ 155‒158. Back

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application of the duty to investigate, on the one hand, and the need to ensure compliance with the overarching requirement of effectiveness, on the other hand. According to this test, the standards of effectiveness must in principle be followed even in difficult security conditions and armed conflict, yet they are to be applied in a manner that is mindful of the special circumstances characterising these situations.

What is reasonable or feasible in a given context can only be established on a case-by-case basis and according to the concrete circumstances. In the Al-Skeini case, concerning the killing of six Iraqi civilians by British soldiers in southern Iraq, the ECtHR criticized the UK authorities for starting the investigation with excessive delay as well as for the lack of thoroughness and transparency in conducting it. 48 Even during a security patrol marked by exchanges of live fire, the Court considered it feasible for investigators to act in a more prompt and thorough manner. In the Jaloud case, regarding the fatal shooting of an Iraqi civilian by a Dutch soldier at a checkpoint, the Court found the Netherlands in breach of the procedural duty to investigate under Art. 2 ECHR. In this instance, it condemned the investigators’ inability to retrieve certain evidence and attend the autopsy, and the failure to separate the soldier responsible for the shooting from his fellow soldiers. 49 Interestingly, seven judges criticized the ECtHR for what they considered an excessively thorough scrutiny of the respondent State’s conduct, and especially for requiring it to perform unfeasible tasks, given the concrete circumstances and the security situation. 50 The Jaloud judgment shows that the feasibility or reasonableness of certain investigative acts may be interpreted in very different manners even within the same adjudicating body.

For present purposes, the point to retain is that the ‘all reasonable steps/all feasible measures’ test appears to find a workable equilibrium between the practical obstacles an investigating State may face in these contexts and the requirement that such a State always investigate alleged human rights violations as effectively as possible. As shown below, the ‘reasonable’ or ‘feasible’ steps a State may be required to undertake to investigate effectively might extend to arranging investigative cooperation agreements with the other actors involved in a peace operation. 51

III. The Obligation to Investigate under IHL

Under IHL, the sources of the obligation to investigate are primarily found in the treaty law applicable to international armed conflicts. The Geneva Conventions (GCs) and Additional Protocol I (AP I) establish that States must investigate and prosecute alleged perpetrators of so-called grave breaches, i.e. those violations explicitly listed in certain specific provisions. 52 The treaty law applicable to non-international armed conflicts, namely Common Art. 3 of GCs and Additional Protocol II (AP II), do not present equivalent provisions. However, thanks to the impulse given by international criminal tribunals, 53 it is generally acknowledged that customary IHL requires States to investigate acts qualifying as war crimes 54 in both international and non-international armed conflicts. 55 This duty is also included in a number of treaties dealing with
48 ECtHR, Al-Skeini, supra note 21, §§ 169‒174 . Back
49 ECtHR, Jaloud, supra note 24, §§ 197‒216. Back
50 Id. , Joint Concurring Opinion of Judges Casadevall, Berro-Lefevre, Šikuta, Hirvelä, López Guerra, Sajó and Silvis, §§ 6‒8. Back
51 See below Section VII. Back
52 GC I, Arts. 49–50; GC II, Arts. 50–51; GC III, Arts. 129–130; GC IV, Arts. 146–147; AP I, Arts. 11, 85. Grave breaches are part of the broader category of war crimes; see AP I, Art. 85(5). Back
53 S. Darcy, Judges, Law and War: The Judicial Development of International Humanitarian Law (Cambridge, Cambridge University Press, 2014), pp. 279 ff. Back
54 A war crime is a violation of a conventional or customary rule of IHL that is serious in nature, namely which breaches a norm protecting important values and involves grave consequences for the victim, and that engages the individual criminal responsibility of the perpetrator; see ICTY, Tadić, supra note 11, § 94. Back
55 J.M. Henckaerts and L. Doswald-Beck (eds.), Customary International Humanitarian Law (Cambridge, Cambridge University Press, 2005), p. 607. See also IACtHR, El Mozote, supra note 47, § 286. Back

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specific means and methods of warfare, 56 as well as in the Rome Statute of the International Criminal Court (ICC), 57 which cover both types of armed conflict. In general, IHL criminalizes acts equivalent to extra-judicial killings, torture and ill-treatment, and enforced disappearances. 58

An element that needs to be considered in relation to the duty to investigate alleged war crimes is the threshold to open an investigation. According to a study conducted by the Turkel Commission, State practice shows that not all allegations of war crimes are to be investigated: the obligation to investigate only arises when a ‘credible allegation’ or a ‘reasonable suspicion’ exists that a war crime has been committed. 59 This conclusion is supported by a number of commentators. 60 The existence of a threshold to open an investigation under IHL is deemed to reflect the context of armed conflict and the specific features of this body of law. 61 IHL is in fact designed to regulate armed conflict, and particularly the conduct of hostilities. Its rules are based on a calibration between humanity and military necessity, which translates into norms allowing the use of force against lawful targets, be they objects or persons. As a consequence, not all allegations concerning death among civilians or destruction of civilian objects in the conduct of hostilities warrant an investigation: the duty to investigate is triggered when a credible allegation is made or a reasonable suspicion arises that a war crime has been committed. The specific circumstances and context in which an alleged IHL violation occurs, especially when civilian casualties are involved, will in fact determine the necessity to open an investigation. 62 At the same time, potentially unlawful death committed outside the conduct of hostilities, e.g. while the victim is in custody, must always be investigated. 63 The same goes for those acts that are prohibited under any circumstances, such as rape or torture. 64 Competent authorities should also carry out a fact-finding assessment whenever an allegation does not meet the threshold to open an investigation, and there is a need for further ascertainment of the circumstances surrounding an incident. Such fact-finding activity should aim to verify and consolidate allegations with a view to assessing whether a criminal investigation is warranted. 65

Effectiveness is a crucial element of war crimes investigations as well. The GCs and AP I do not contain provisions indicating how investigations should be conducted and do not provide general guidance to evaluate the effectiveness of an investigation. Some elements can be found in Arts. 121 of GC III and 131 of GC IV, which prescribe the basics of an investigation into the death or serious injury of prisoners of war and civilian internees: promptness, collection of evidence, and prosecution of the perpetrators. 66 Whereas IHL treaties do not further regulate the
56 Among others, see Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction, Geneva, 3 September 1992, 1974 UNTS 45, Art. VII(1); Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on their Destruction, Oslo, 18 September 1997, 2056 UNTS 211, Art. 9. Back
57 ICC Statute, Arts. 1, 17, 53. Back
58 Henckaerts and Doswald-Beck, supra note 55, pp. 568–603. Back
59 Public Commission to Examine the Maritime Incident of 31 May 2010, Israel’s Mechanisms for Examining and Investigating Complaints and Claims of Violations of the Laws of Armed Conflict According to International Law, Second Report, February 2013 (Turkel Commission), p. 256. The Turkel Commission surveyed the legislation and practice of the US, Canada, Australia, the UK, Germany, and the Netherlands. See also id. , Annex C, The Comparative Survey. Back
60 Schmitt, supra note 40, pp. 39, 83; Cohen & Shany, supra note 39, p. 51. See also Minnesota Protocol, supra note 26, § 21. Back
61 Minnesota Protocol, supra note 26, § 20. Back
62 Turkel Commission, supra note 59, p. 102. Back
63 Minnesota Protocol, supra note 26, § 16. Back
64 Turkel Commission, supra note 59, pp. 100‒101. Back
65 Id. , pp. 102‒103; Minnesota Protocol, supra note 26, § 21; Report of the Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms while Countering Terrorism, UN Doc. A/68/389, 18 September 2013, §§ 42‒43. Fact-finding assessment may be used even in cases of unanticipated collateral damage when there is no prima facie case of the commission of a war crime. Back
66 GC III, Art. 121: “1. Every death or serious injury of a prisoner of war caused or suspected to have been caused by a sentry, another prisoner of war, or any other person, as well as any death the cause of which is unknown, shall be immediately followed by an official enquiry by the Detaining Power. 2. […] Statements shall be taken from witnesses, especially from those who are prisoners of war […]. 3. If the enquiry indicates the guilt of one or more persons, the Detaining Power shall take all measures for the prosecution of the person or persons responsible”. The text of Art. 131 of GC IV is substantially identical. See also ICRC, Guidelines for Investigating Death in Custody, 21 November 2013, https://www.icrc.org/en/publication/4126-guidelines-investigating-deaths-custody. Back

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standards of effectiveness, international case law on command responsibility offers some indications on the overarching requirement of effectiveness. 67 In this respect, the ICTY held that: “A superior’s duty to punish the perpetrators of a crime may encompass an obligation to conduct an effective investigation with a view to establishing the facts”. 68 Both the ICTY and the ICC stressed the need for an investigation to be effective or adequate. 69 Given that the circumstances on the ground shape a commander’s duty to punish and that an evaluation must be made on a case-by-case basis, international case law does not offer further specification of how to assess effectiveness. However, the ICTY affirmed that “the Tribunal’s case law has established a minimum standard for measures that may fulfil the duty to punish. A trial chamber must look at what steps were taken to secure an adequate investigation capable of leading to the criminal prosecution of the perpetrators”. 70 In that sense, the ICTY referred to the principle of effectiveness in terms that are similar to those employed by human rights bodies.

Moreover it is widely acknowledged that, when carrying out war crimes investigations, States should in principle follow the standards of effectiveness set by human rights law. 71 The applicability of such standards to war crimes investigations is a result of the concurrent application of IHL and human rights law in armed conflict. In this respect, two main interpretive trends have emerged: (1) IHL and human rights law are complementary legal frameworks that reinforce each other, the consequence of which is that norms from one body of law may be used to fill the gaps in the other; 72 (2) when diverging rules concurrently apply and norm conflict may potentially arise, human rights norms can be interpreted in light of IHL. 73 The result of this second interpretation is that an act that in peacetime would qualify as a breach of human rights law ‒ e.g. law enforcement agents using lethal force as first resort against the boss of a drug cartel ‒ may not be deemed so in situations of armed conflict ‒ e.g. a lethal airstrike against the commander of an organized armed group. The reverse side of this reasoning is that a violation
67 Under Art. 87 of AP I, commanders bear the two distinct duties to prevent and to punish IHL violations. In relation to the duty to punish, a commander must examine all allegations concerning breaches of IHL, and investigate or report to competent authorities allegations of war crimes. He or she is required to take all necessary and reasonable measures in light of the concrete circumstances. See G. Mettreaux, The Law of Command Responsibility (New York, Oxford University Press, 2009), p. 235, and the case law cited therein. Back
68 ICTY, Prosecutor v. Boškoski and Tarčulovski, Case IT-04-82-T, Trial Chamber, 10 July 2008, § 418 (emphasis added). See also ICC, Prosecutor v. Jean-Pierre Bemba Gombo, Case ICC-01/05-01/08, Trial Chamber III, 21 March 2016, §§ 205‒209. Back
69 ICTY, Prosecutor v. Strugar, Case IT-01-42-T, Trial Chamber, 31 January 2005, §§ 376, 378; Prosecutor v. Popović et al, Case IT-05-88-A, Appeals Chamber, 30 January 2015, § 1932; ICC, Bemba, supra note 68, §§ 207‒208, 727‒728, 733. Although relevant case law concerns the individual responsibility of commanders to discharge their duties under international law, effectiveness may be deemed an overarching requirement that attaches to a State’s obligation to investigate alleged war crimes. Back
70 ICTY, Popović, supra note 69, § 1932 (emphasis added). Back
71 Report of the United Nations Fact-Finding Mission on the Gaza Conflict, UN Doc. A/HRC/12/48, 25 September 2009, §§ 1808, 1814; Special Rapporteur on Human Rights and Counterterrorism, supra note 65, § 43; Turkel Commission, supra note 59, p. 115; Schmitt, supra note 40, pp. 55‒56; Cohen & Shany, supra note 39, p. 59; Murray et al., supra note 15, pp. 334‒335. It should be highlighted that as a matter of domestic law, policy, and/or practice some States already make use of the standards of effectiveness when investigating alleged criminal acts committed by members of their armed forces; see Turkel Commission, supra note 59, pp. 261‒264. Back
72 HRC, General Comment 31, supra note 15, § 11; IACtHR, Serrano-Cruz Sisters v. El Salvador, 23 November 2004, Series C No. 118, §§ 111–116; IAComHR, Franklin Guillermo Aisalla Molina (Ecuador–Colombia), Report No. 112/10, 21 October 2010, § 121. Back
73 ICJ, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, ICJ Reports 1996, 240, § 25; IAComHR, Coard v. United States, Report No. 109/99, 29 September 1999, § 42; HRC, General Comment 35, supra note 23, § 64; HRC, General Comment 36, supra note 15, § 64; IACtHR, Santo Domingo, supra note 47, §§ 211 ff.; AComHPR, General Comment 3, supra note 18, § 32; ECtHR, Hassan v. United Kingdom, Appl. No. 29750/09, 16 September 2014, § 104. Back

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of the IHL rule in light of which the human rights norm is construed a fortiori implies a violation of the latter. 74 For present purposes, the most relevant legal effect is that the concurrent violation of IHL and human rights law makes the standards of effectiveness applicable to war crimes investigations. 75 The context of an armed conflict and the applicability of IHL, however, have a bearing on how the standards of effectiveness are to be applied. Although the ‘all reasonable steps/all feasible measures’ test allows tailoring their application according to the specific circumstances, a number of points need to be considered.

A first point concerns the threshold for opening an investigation. While under IHL a credible allegation or reasonable suspicion that a war crime has been committed must exist, under human rights law an investigation has instead to be conducted as soon as State authorities are aware of an alleged violation. In relation to the conduct of hostilities, the threshold for opening an investigation will be set by IHL. In such a context, as mentioned above, the violation of human rights norms on the use of force will be dependent upon a violation of IHL, which provides for less restrictive rules on targeting individuals. In respect of violations occurring outside the conduct of hostilities, e.g. the killing of a detained person, the lower threshold set by human rights law should apply. 76 A lower threshold should also guide the opening of an investigation for those IHL violations that must be investigated under any circumstances, such as rape or torture.

A second point regards the independence and impartiality of investigatory bodies. IHL does not require an investigation to be conducted outside the military, nor does it necessarily favour the employment of prosecutorial over administrative investigatory authorities in carrying out criminal investigations. 77 At the same time, human rights bodies have pointed out that investigations carried out by the military into alleged human rights violations committed by State armed forces tend to lack independence and impartiality. 78 Human rights law more generally disfavours the exercise of jurisdiction over human rights violations by military courts. 79 With reference to extraterritorial military operations, the ECtHR did not exclude that investigators belonging to the military are capable of meeting these requirements. 80 What matters in this respect is that both formal and factual independence and impartiality from the operational chain of command be ensured, so that investigators are not subjected to undue interference. 81 Since IHL allows for investigations into alleged war crimes to be conducted by military personnel, States may avail themselves of this option. Yet, human rights law will play a role in defining whether military investigative authorities comply with the requirements of independence and impartiality. 82

A third point concerns promptness and thoroughness. These standards will need to be applied taking into account the security conditions investigatory bodies might face, for example in opening an investigation promptly. 83 This evaluation must necessarily be made on a case-by-case basis, and a State is required to prove what concrete hindrances have impeded to conduct a
74 IAComHR, Coard, supra note 73, §§ 52–61; IACtHR, Santo Domingo, supra note 47, §§ 230, 237 ; AComHPR, General Comment 3, supra note 18, § 32; ECtHR, Hassan, supra note 73, § 105. Back
75 For further analysis on this point, see V. Todeschini, ‘Investigations in Armed Conflict: Understanding the Interaction between International Humanitarian Law and Human Rights Law’, in P. De Hert, S. Smis and M. Holvoet (eds.), Convergences and Divergences Between International Human Rights, International Humanitarian and International Criminal Law (Antwerp, Intersentia, 2018). Back
76 Minnesota Protocol, supra note 26, § 16, 20. Back
77 GC IV, Art. 146; AP I, Art. 87. Back
78 IACtHR, Velásquez Rodríguez, supra note 32, § 180; International Commission of Jurists, supra note 20, pp. 158‒159, and case law cited therein. Back
79 Updated Impunity Principles, supra note 15, Principle 29. Back
80 ECtHR, Jaloud, supra note 24, §§ 187‒190. Back
81 ECtHR, Al-Skeini, supra note 21, §§ 171‒174. Back
82 In a similar vein, see ECtHR, Hassan, supra note 73, § 106. Back
83 ECtHR, Al-Skeini, supra note 21, § 164. Back

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full investigation. 84 This will especially concern alleged violations of the right to life connected to the conduct of hostilities, particularly when the allegedly responsible State has no control over the area where an incident happened. 85 It is precisely in these circumstances that the obligation to investigate demands a State to take all reasonable steps or feasible measures to investigate as effectively as possible.

A fourth point is connected with transparency. Similarly to the other standards of effectiveness, transparency must be balanced with the specific circumstances surrounding an incident that occurs in armed conflict: a State’s own security might be a relevant factor to be considered in this respect. 86 Yet, the outcome of an investigation should in some way be accessible to the general public for accountability purposes; and, victims or their next of kin should have some form of access to the investigative files as well as the possibility to challenge decisions concerning the closure of an investigation and the non-prosecution of the allegedly responsible individuals. 87 Indeed, while IHL does not envisage a requirement of transparency with regard to investigations, this standard pursues the objectives of increasing compliance with the law and deterring future violations, which are central to the duty to investigate under IHL. 88

IV. The Need for Investigative Cooperation

While IHL and human rights law impose on States an obligation to investigate as effectively as possible under any circumstances, the context of peace operations add some further challenges in this respect. Indeed, in order to discharge the obligation to investigate in peace operations, TCSs may need some form of collaboration from other actors. The degree of cooperation required varies according to the actor considered. The host State’s authorisation is always required to carry out certain investigative activities, e.g. accessing the crime scene; collaboration from the leading international organization or other TCSs might also be needed, e.g. for questioning the former’s officials or the latter’s military personnel. Under this perspective, investigative cooperation becomes one of the elements determining a TCS’s ability to conduct an investigation effectively and to comply with its relevant obligations under IHL and human rights law. Some examples are useful to illustrate how the lack of cooperation may affect a State’s ability to investigate.

The ECtHR’s Jaloud case provides an account of the unwillingness of the host State to collaborate fully with a sending State. In the case, an Iraqi civilian was shot and killed by a Dutch lieutenant at a checkpoint. Soon thereafter, Dutch authorities opened an investigation into the incident. Since the Netherlands did not have the necessary facilities to conduct an autopsy, the body of Mr. Jaloud was transferred to a local hospital so that this could be conducted by Iraqi personnel. Subsequently, local authorities decided to exclude the Dutch personnel from attending the autopsy, 89 a choice that the Netherlands, in absence of agreed-upon terms of cooperation, could not oppose at the legal level. 90 Furthermore, Dutch investigative authorities could not locate and retrieve the collected fragments of the bullets that had killed Mr. Jaloud, because the report redacted by the Iraqi authorities did not specify where such evidence had
84 IAComHR, Molina, supra note 72, § 157. Back
85 Minnesota Protocol, supra note 26, § 20. Back
86 Report of the Committee of Independent Experts in International Humanitarian and Human Rights Laws to Monitor and Assess any Domestic, Legal or Other Proceedings Undertaken by both the Government of Israel and the Palestinian Side, in the light of General Assembly Resolution 64/254, including the Independence, Effectiveness, Genuineness of these Investigations and their Conformity with International Standards, UN Doc. A/HRC/15/50, 23 September 2010, § 32. Back
87 ECtHR, Al-Skeini, supra note 21, § 174. See also HRC, General Comment 36, supra note 15, § 64. Back
88 Turkel Commission, supra note 59, §§ 106–107. Back
89 ECtHR, Jaloud, supra note 24, § 180. Back
90 On top of that, the situation at the Iraqi hospital was apparently so tense that the Dutch personnel were worried for their own security. This led them not to insist with their demands and eventually leave the facility; see id. , Joint Concurring Opinion of Judges Casadevall et al., § 6. Back

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been stored. 91 It must be noted that, in absence of a clear obligation to cooperate, it is part of the host State’s sovereign prerogative not to give authorisation to a TCS’s investigators to carry out or attend an autopsy performed on the body of a local citizen. The same goes for the refusal by the host State to hand over to a TCS evidence or other items connected to an incident.

Another example of a host State’s lack of cooperation regards the so-called Colonel Klein case. This case concerned an airstrike in the Afghan region of Kunduz against fuel trucks, which German forces suspected the Taliban might use to conduct an attack against a nearby military base, and which resulted in several civilian casualties. In such an instance, German authorities were prevented from conducting an effective on-site investigation. In particular, they could not exhume the bodies of the victims, which were in control of the Afghan police, in order to carry out the necessary autopsies and forensic examinations. 92

A case of non-cooperation on the side of the leading international organization regards the Multidimensional Integrated Stabilization Mission in the CAR (MINUSCA), a UN operation supported by non-UN French forces, in which allegations arose of acts of sexual exploitation and abuse committed by members of the French contingent against local children and women. French investigators were sent to the CAR after such allegations had been brought to the attention of competent French authorities. When they requested to hear the testimony of the UN officer that had interviewed the alleged victims, the UN Office of Legal Affairs asserted immunity, 93 thus preventing such officer from being interviewed; immunity was waved only one year later. 94 It is also reported that the UN generally acted in a way that considerably slowed down the pace of the investigation conducted by French authorities. 95 Finally, one must mention that an investigating TCS may need the cooperation of other TCSs, e.g. with regard to equipment for conducting autopsies. A refusal by the latter to cooperate may lead to the former being incapable of conducting investigations effectively. 96

V. Criminal Jurisdiction and Investigative Cooperation in the UN Model SOFA and MOU

In UN operations, Status of Forces Agreements (SOFAs) and Memorandums of Understanding (MOUs) regulate, to a certain degree, investigative cooperation between participants. In general, States stationing or deploying troops in another country usually negotiate a SOFA with the host State. These agreements define various aspects connected to the presence of State armed forces in foreign territory, the so-called jus in praesentia: the right to entry, passage, and leave; carrying of weapons and wearing of uniforms; taxes and customs; civil and criminal jurisdiction. 97 Except for the UN Model SOFA, 98 there is no generally-accepted model agreement under international law: SOFAs are tailored according to the purpose of the stationing or deployment of troops. From an international law viewpoint, they are binding bilateral agreements regulated by the law of treaties. 99 When troops are deployed in peace
91 Id. , § 36. Back
92 Turkel Commission, supra note 59, Annex C: Germany, §§ 141–142. For the original decision, see Bundesgeneralanwalt beim Bundesgerichtshof, 3 BJs 6/10-4, 16 April 2010 (in German only). Back
93 Convention on the Privileges and Immunities of the United Nations, New York, 13 February 1946, 1 UNTS 15, Section 18: “Officials of the United Nations shall: a) be immune from legal process in respect of words spoken or written and all acts performed by them in their official capacity [...]”. Back
94 Deschamps, Jallow & Sooka, supra note 3, pp. 46–47. Back
95 Id. Back
96 The present author was unable to find real-life examples in case law or reports. Back
97 For example, NATO elaborated a model SOFA that is used to regulate the stationing of troops among allied countries; see Agreement between the parties to the North Atlantic Treaty regarding the status of their forces, London, 19 June 1951, 199 UNTS 67 (NATO SOFA). Back
98 Model Status-of-Forces Agreement for Peace-Keeping Operations, UN Doc. A/45/594, 9 October 1990, (UN Model SOFA). A model SOFA exists also for EU-led operations; Draft Model Agreement on the Status of the European Union-led Forces between the European Union and a Host State, Doc. 11894/07, 20 July 2007. Back
99 J. Voetelink, ‘The Status of Foreign Forces in Afghanistan post 2014’, Vol. 108 Mil.R.T. 2015, p. 3. In the majority of circumstances, the conclusion of SOFAs will be the result of negotiations between a State or an international organization and the host State. With regard to UN-led operations, the Security Council sometimes imposes the applicability of the UN Model SOFA pending the conclusion of a mission-specific SOFA; see among others UN Doc. S/RES/1159, 27 March 1998, operative § 19. When States do not intend to or cannot reach a binding agreement, they resort to MOUs, which are generally not governed by international law and not binding on parties. However, see Memorandum of Understanding between the United Nations and [Participating State] Contributing Resources to [the United Nations Peacekeeping Operation] , 29 January 2009, UN Doc. A/C.5/63/18, p. 161 (UN Model MOU), Art. 3. Differently to the generality of MOU, the UN Model MOU is a binding agreement between the UN and TCSs; see Z. Deen-Racsmány, ‘The Amended UN Model Memorandum of Understanding: A New Incentive for States to Discipline and Prosecute Military Members of National Peacekeeping Contingents?’, Vol. 16 J.C.S.L. 2011, p. 335. Back

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operations, the leading international organization or State typically negotiates mission-specific SOFAs covering both the operation as such and its personnel. 100 When a mission-specific SOFA is negotiated between the leading international organization or State and the host State, TCSs are not parties to it but become beneficiaries of its provisions. 101

Among other matters, SOFAs regulate the exercise of criminal jurisdiction over military personnel. Typically, TCSs retain exclusive criminal jurisdiction over national contingents deployed in peace operations. 102 This rule is part of an established practice characterising both UN-led and UN-authorised operations; 103 according to some commentators, it has acquired customary status. 104 In general terms, SOFAs allocate the jurisdiction to adjudicate and to enforce: although armed forces are subject to both the sending and the host State’s criminal laws ‒ the jurisdiction to legislate ‒ the host State cannot exercise over them its jurisdiction to adjudicate and enforce, which remains an exclusive prerogative of the sending State. 105 The exclusive jurisdiction clause included in SOFAs implies that TCSs always retain the obligation to investigate alleged war crimes and human rights violations committed by their military personnel. 106 This applies even when an international organization is vested with exclusive operational control over multinational forces – which typically occurs in UN-led operations – as testified by the inclusion of such clauses in the UN Model SOFA and MOU. 107

Such an arrangement effectively results in immunity from local criminal proceedings for the armed forces of the sending States. 108 Although SOFAs do not deal with immunities as such, in the context of peace operations jurisdiction and immunities are intertwined. While immunities are concerned with barring the host State from conducting criminal proceedings against a foreign official, SOFAs place the emphasis on the faculty of a TCS to exercise criminal jurisdiction over the alleged perpetrators of a violation. 109 Indeed, TCSs have an obligation to
100 O. Engdahl, Protection of Personnel in Peace Operations: The Role of the ‘Safety Convention’ against the Background of General International Law (Leiden, Martinus Nijhoff, 2007), pp. 151‒152. Back
101 Id. , p. 151. Back
102 UN Model SOFA, supra note 98, § 47(b); UN Model MOU, supra note 99, Art. 7 quinquiens. The retention of exclusive criminal jurisdiction by TCSs is peculiar to operational contexts. Outside the latter situation, concurrent jurisdiction tends to be the rule; see NATO SOFA, Art. VII; B. van Hoek, J. Nijhof & J. Voetelink, ‘The Scope of Jurisdiction Provisions in Status of Forces Agreements Related to Crisis Management Operations’, Vol. 51, M.L.L.W.R. , p. 347. Back
103 Engdahl, supra note 100, pp. 183 ff. For an historical excursus of the origin of the exclusive jurisdiction rule, see J. Voetelink, Status of Forces: Criminal Jurisdiction over Military Personnel Abroad (The Hague, T.M.C. Asser Press, 2015), pp. 23‒32. Back
104 Id. , pp. 184‒185; Engdahl, supra note 100, pp. 193‒201. Back
105 van Hoek, Nijhof & Voetelink, supra note 102, pp. 342‒343. Back
106 This does not deprive the host State of the right to initiate an investigation, as long as it does not overstep into the exclusive jurisdiction of sending States. Furthermore, third States may exercise universal jurisdiction for international crimes; see Engdahl, supra note 100, pp. 190‒191. Under certain circumstances, the UN is entitled to undertake fact-finding inquiries or administrative investigations. See below note 122 and accompanying text. Back
107 UN Model SOFA, supra note 98, § 47(b); UN Model MOU, supra note 99, Art. 7 quinquiens. Back
108 Immunities flow from the principles of State sovereignty and the equality of States under international law. They are designed to strike a balance between the right of the sending State to perform unimpededly official acts and the right of the host State to exercise jurisdiction over its territory. Since armed forces are State organs performing official duties, military personnel are covered by State immunities even when no SOFA is in place; see F. Hampson, Working Paper on the Accountability of International Personnel Taking Part in Peace Support Operations, UN Doc. E/CN.4/Sub.2/2005/42, 7 July 2005, § 16. Back
109 Voetelink, supra note 103, pp. 12‒16. Back

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ensure that military members of their national contingents be held to account for both criminal and non-criminal acts. Sending States are supposed to act in good faith, and their exclusive entitlement to exercise jurisdiction should not result in impunity for their military personnel. 110

In addition, it is useful to recall that a TCS’s authority to investigate is an aspect of its jurisdiction to enforce, 111 which primarily has a territorial dimension. Although SOFAs do not define the boundaries and content of the term ‘jurisdiction’, it is acknowledged that the exclusive jurisdiction clause covers both the jurisdiction to adjudicate and to enforce, and in principle provides TCSs with the authority to investigate in an extraterritorial context. 112 At the same time, a sending State’s authority to investigate has limitations. To conduct investigations in another State’s territory, thus to exercise extraterritorially the jurisdiction to enforce, a State needs the host State’s consent or another basis under international law. This owes to the rule according to which States must respect each other’s sovereignty. 113 Furthermore, a State’s authority to investigate is limited vis-à-vis the officials of an international organization or the military personnel of other States. In absence of a waiver, the immunities enjoyed by these persons may prevent a TCS’s investigating authorities to hear them as witnesses. 114 The question then is whether these aspects are regulated in peace operations.

The clearest answer is provided by the relevant agreements applicable in UN operations, i.e. the UN Model SOFA and MOU, 115 which regulate the relationship of the UN with the host State and TCSs, respectively. The UN Model SOFA provides that:
The United Nations peace-keeping operation and the Government shall assist each other in carrying out all necessary investigations into offences in respect of which either or both have an interest, in the production of witnesses and in the collection and production of evidence, including the seizure of and, if appropriate, the handing over of items connected with an offence. 116
This clause establishes a mutual obligation to cooperate in investigative matters between the UN and the host State. Some NATO mission-specific SOFAs envisage a similar cooperation clause, albeit in less specific terms; 117 at times, the obligation to cooperate rests on the host State only. 118

While the UN Model SOFA does not mention the need for the host State’s consent in order to conduct investigations on its territory, the UN Model MOU clearly spells out this requirement:
The competent authorities of the Government [the investigating TCS] shall ensure that prior authorization for access to any victim or witness who is not a member of the national contingent, as well as for the collection or securing of evidence not under the ownership and control of the national contingent, is obtained from the host nation competent authorities. 119
When read together, the provisions contained in the UN Model SOFA and MOU establish the following: (1) a TCS always needs the cooperation of the host State to carry out investigative activities that may involve the local population or impinge on the latter’s sovereignty; (2) the
110 UN Model SOFA, supra note 98, § 48; UN Model MOU, supra note 99, Art. 7 sexiens. Back
111 State jurisdiction to prescribe, to adjudicate, and to enforce should not be confused with jurisdiction under human rights treaties. See above Section II. Back
112 van Hoek, Nijhof & Voetelink, supra note 102, p. 354. Back
113 Voetelink, supra note 103, p. 119. Back
114 In relation to UN officials, see Convention on the Privileges and Immunities of the UN, supra note 93, Section 18(a). Back
115 As noted, both the UN Model SOFA and MOU constitute binding agreements between the UN and the host State, on the one hand, and the UN and TCSs, on the other hand. See above note 99. Back
116 UN Model SOFA, supra note 98, § 44. It is worth mentioning that this provision reproduces almost verbatim Art. VII(6)(a) of the NATO SOFA, supra note 97. Back
117 General Framework Agreement for Peace (GFAP) in Bosnia and Herzegovina, Appendix B to Annex 1A, Paris, 14 December 1995, 35 I.L.M. 75, at < http://www.nato.int/ifor/gfa/gfa-ap1a.htm> (IFOR SOFA), Art. 7. Back
118 Military Technical Agreement between the International Security Assistance Force (ISAF) and the Interim Administration of Afghanistan, Annex A, 4 January 2002, 41 I.L.M. 1038 (ISAF SOFA), Art. 1(3). Back
119 UN Model MOU, supra note 99, § 7.17. Back

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host State has an obligation to cooperate with the UN and, indirectly, with the investigating TCS. In addition, the UN Model MOU regulates in a detailed manner investigative cooperation between the UN and TCSs. 120 In accordance with the exclusive jurisdiction rule, the UN Model MOU acknowledges that TCSs have the primary responsibility for investigating alleged criminal acts and misconduct committed by military members of their national contingent. 121 The UN may conduct a preliminary fact-finding inquiry for purposes of preserving evidence, or initiate an administrative investigation when the sending State is considered unwilling or unable to proceed, particularly if no action is taken after ten working days from the emergence of relevant allegations. 122 The primacy of TCSs with regard to investigations is reflected in several clauses of the UN Model MOU: the UN may conduct fact-finding activities only when the TCS does not; representatives of the TCS must be included in any UN administrative investigations; national authorities always have the prerogative to lead an investigation, even if the UN is already investigating. 123 Importantly, sending States and the UN must cooperate and share information, documentation and findings between each other. 124 The UN is also required to provide administrative, logistic and financial support to the deployment of national investigative teams. 125 A crucial element for the sake of investigative cooperation is the liaising role the UN must play between the investigating TCS, the host State, and other TCSs. 126 This is particularly relevant in light of the fact that the UN, not the sending State, is the party to the SOFA. In sum, the UN Model SOFA and MOU provide a framework that determines a TCS’s authority to investigate in operational contexts. These documents also regulate cooperation with the host State and the UN, both of which have a duty to collaborate in the investigation. It is finally worth noting that NATO operations do not present similarly detailed agreements for the regulation of investigative cooperation. 127

VI. Investigative cooperation: Mapping the Normative Gaps

In the following sections, the framework set in the UN Model SOFA and MOU will be employed as a benchmark to map the normative gaps regarding investigative cooperation in three distinct scenarios: UN operations; UN operations supported by non-UN forces and NATO operations. 128

1. UN Operations

As discussed, the UN Model SOFA establishes a duty to cooperate between the UN and the host State, while the UN Model MOU regulates cooperation between the UN and TCSs. The UN Model MOU further establishes that:
120 Id. , Art. 7 quater. Previously to the amendment of the UN Model MOU in 2007, investigations in UN peacekeeping operations were governed ‒ together with all other aspects of an operation ‒ by the UN Model SOFA, the 1991 Troop Contribution Agreement, and the Directives for Disciplinary Matters Involving Military Members of National Contingents. For an analysis of these documents, see Deen-Racsmány, supra note 99, pp. 324‒332. Back
121 UN Model MOU, supra note 99, § 7.10. Back
122 Id. , §§ 7.12‒7.13. Back
123 Id. , §§ 7.12‒7.13, 7.18. Back
124 Id. , §§ 7.14‒7.16, 7.18. The UN Model MOU recognises that the disclosure of an investigation’s findings to the UN may be subject to the TCS’s domestic laws and regulations; id. , § 7.19. Back
125 Id. , § 7.21. Back
126 Id. , § 7.17. Back
127 van Hoek, Nijhof & Voetelink, supra note 102, pp. 353‒355. See below Section VI 3. Back
128 This categorisation does not bear any legal significance. It is adopted for the sole purpose of examining how the different structures of the said operations affect the way investigative cooperation is regulated. Back

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Upon the request of the Government, the United Nations shall cooperate with the competent authorities of the Government, including any National Investigations Officers, that are investigating possible misconduct or serious misconduct by any members of its national contingent, by liaising with other Governments that are contributing personnel in support of [a UN peacekeeping mission], as well as with the competent authorities in the mission area, with a view to facilitating the conduct of those investigations. To this end, the United Nations shall take all possible measures to obtain consent from the host authorities. 129
This provision makes clear that the UN is supposed to play a liaising role between the investigating TCS, on the one hand, and other TCSs or the host State, on the other hand. While the UN Model SOFA and MOU provide a rather detailed regulation of investigative cooperation in UN operations, one issue remains unaddressed. The UN Model MOU governs investigative cooperation between the UN and TCSs, yet it does not establish an obligation on TCSs to cooperate with the investigating TCS. 130 As a consequence, faced with a refusal by a TCS to provide assistance, e.g. in relation to equipment for conducting autopsies, the investigating TCS might not be capable of carrying out an effective investigation. This in turn may impact such a State’s ability to comply with its obligation to investigate under human rights law and IHL. In the present author’s view, this constitutes a normative gap within the legal framework governing investigative cooperation in UN operations.

2. UN Operations supported by non-UN Forces

The picture becomes more complicated when UN operations are supported by TCSs acting outside the UN chain of command. With regard to MINUSCA, the UN-led operation in the CAR supported by the French Sangaris force, investigative cooperation between the UN, the CAR, and TCSs is regulated by the UN mission-specific SOFA and MOU. The relationship between France and the CAR, on the other hand, is regulated by a separate SOFA between the two countries. Differently from the UN Model SOFA, non-UN mission-specific SOFAs do not usually regulate in detail investigative cooperation between a TCS and the host State. 131 For analytical purposes, it may be assumed that the SOFA concluded between France and the CAR is no exception and does not include a specific provision in this respect. 132 Such a lack of regulation constitutes a first normative gap, which could negatively affect France’s ability to conduct an effective investigation in absence of full collaboration on the part of the CAR.

The lack of agreements governing investigative cooperation between the UN operation and non-UN forces reveals two other normative gaps: one concerns the relationship between France and the UN; another regards the relationship between France and any of the UN-commanded TCSs. In this respect, France could not invoke an obligation to cooperate vis-à-vis both the UN and UN-commanded TCSs. The same goes the other way around, i.e. if France was requested to cooperate with the UN or any of the UN-commanded TCSs. This in turn entails that a TCS may be precluded from conducting an effective investigation as prescribed by human rights law and IHL. In summary, the present scenario is characterised by three normative gaps relating to investigative cooperation, which arise from the lack of agreements or insufficient regulations between (1) non-UN forces and the host State; (2) non-UN forces and the UN; and (3) non-UN forces and UN-commanded TCSs.

3. NATO Operations

Differently to the UN, NATO has not elaborated model agreements for operational contexts. 133 It is therefore necessary to analyze whether and how mission-specific agreements regulate investigative cooperation. The SOFA for the Implementation Force in Bosnia Herzegovina (IFOR) provides that “NATO and the authorities of the Republic of Bosnia and Herzegovina
129 UN Model MOU, supra note 99, § 7.17. Back
130 In this respect, TCSs are in a different position than the host State, which is explicitly bound by the UN Model SOFA to provide investigative assistance to the UN, and thus indirectly to the investigating TCS. Back
131 van Hoek, Nijhof & Voetelink, supra note 102, pp. 353‒355. Back
132 The present author could not retrieve any information on the SOFA between France and the CAR. The SOFA between the EU and the CAR, on the other hand, confirms that these agreements usually do not address either the sending States’ authority to investigate in the host State’s territory or investigative cooperation between the two. See Agreement between the European Union and the Central African Republic on the status of the European Union-led forces in the Central African Republic, Doc. L 136/46, 24 May 2008. Back
133 The NATO SOFA regulates the stationing of troops among NATO States outside operational contexts. Back

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shall assist each other in the exercise of their respective jurisdictions”. 134 Although not as detailed as the UN Model SOFA, the wording of the IFOR SOFA ‒ “shall assist” ‒ suggests that NATO and the host State were under a mutual obligation to cooperate in investigations. The Kosovo Force (KFOR) SOFA, while establishing the exclusive criminal jurisdiction of sending States, 135 did not include a provision regulating investigative cooperation.

The International Security Assistance Force (ISAF) SOFA presents a remarkably concise text: 136 “The Interim Administration will assist the ISAF contributing nations in the exercise of their respective jurisdictions”. 137 This clause raises a number of issues. First, while the host State is supposed to assist TCSs in exercising their jurisdiction, the latter do not have the same duty vis-à-vis the former. Second, although parties to the agreement are ISAF and Afghanistan, the SOFA affirms that the host State will directly assist an investigating TCS. This arrangement differs from both the UN Model SOFA and the IFOR SOFA, which establish the obligation to cooperate between the host State and, respectively, the UN and NATO. Such a feature may be explained by the fact that ISAF was originally commanded by sending States; yet, when NATO took over the command of ISAF, it maintained the existing SOFA. 138 Third, one may question whether the wording of such a clause actually imposes on Afghanistan a legal obligation to cooperate. Indeed, the use of the term ‘will’ instead of ‘shall’, which is usually employed in international agreements to signal the binding force of a provision, may cast doubts on the legal effects that attach to the host State.

The SOFA in place for Resolute Support (RS) ‒ the NATO-led operation that substituted ISAF in December 2014 ‒ provides as follows: “In the interests of justice, the Parties shall assist each other in investigation of incidents, including the collection of evidence”. 139 This clause establishes a mutual obligation between the parties – NATO and Afghanistan – to cooperate in investigative matters. Although TCSs retain the obligation to investigate, the subjects of the cooperative duty are NATO and Afghanistan. This is the same arrangement that can be found in the UN Model SOFA and the IFOR SOFA. In addition, the RS SOFA determines that competent investigating authorities “shall take into account any report of investigations by Afghan authorities”. 140 It should be pointed out that a TCS’s investigators will always need to rely on the host State’s investigative findings for those activities, e.g. autopsies, that remain a prerogative of the local authorities. The inclusion of such a provision in the RS SOFA may be explained by a desire on the part of the Afghan government to ensure that, in cases of incidents involving the local population, the findings of its investigative authorities will be duly taken into account by TCSs. Such a conclusion is strengthened by the existence of a distinct clause requiring NATO to keep the Afghan authorities informed about the opening and outcome of criminal proceedings against sending States’ military personnel. 141

To recap, NATO practice shows a certain inconsistency in regulating investigative cooperation in operational contexts. Similarly to the UN Model SOFA, the IFOR and RS SOFAs provide for a mutual obligation to cooperate between NATO and the host State. The KFOR SOFA, instead,
134 IFOR SOFA, supra note 117, Art. 7. The two operations that successively replaced IFOR ‒ the NATO-led Stabilisation Force (SFOR) and the EU-led EUFOR ‒ maintained the same SOFA. Back
135 Status, Privileges and Immunities of KFOR and UNMIK and their Personnel in Kosovo, Regulation No. 2000/47, 18 August 2000, Art. 2.4. Back
136 The ISAF SOFA was adopted when no fully-functioning government existed in Afghanistan. The same SOFA was accepted by the Afghan government that later came into power. Back
137 ISAF SOFA, supra note 118, Art. 1(3). Back
138 Exchange of Letters between NATO and Afghanistan Regarding the Status of NATO and its Personnel when Present on the Territory of Afghanistan in the Execution of ISAF, 5 September 2004 and 22 November 2004 (unpublished), cited in Voetelink, supra note 99, p. 7. Back
139 Agreement between the North Atlantic Treaty Organization and the Islamic Republic of Afghanistan on the Status of NATO Forces and NATO personnel conducting mutually agreed NATO-led activities in Afghanistan, 30 September 2014 (RS SOFA), Art. 11(3). Back
140 Id. , Art. 11(3). Back
141 Id. , Art. 11(2). See also UN Model MOU, supra note 99, §§ 7.19, 7.22, 7.24. Back

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does not regulate the matter at all. The ISAF SOFA, in its own turn, presents ambiguous wording that fails to shed light on the scope and addressees of the obligation to cooperate. It is thus submitted that, with reference to the analyzed NATO mission-specific SOFAs, the absence of a clause clearly regulating investigative cooperation amounts to a normative gap within the legal framework regulating the corresponding peace operations.

As far as the legal relationship between NATO and sending States is concerned, to this author’s knowledge there are no participation agreements equivalent to the UN Model MOU. 142 This constitutes a normative gap insofar as a TCS may need NATO’s cooperation, especially in relation to its liaising role with the host State. Likewise, no agreements appear to exist governing investigative cooperation between TCSs. As discussed, this is a lacuna characterising UN operations as well.

VII. Regulating Investigative Cooperation

The above scenarios show that the regulation of investigative cooperation presents a number of shortcomings, which vary according to the type of operation under consideration. As mentioned, lack of cooperation may impede a State to conduct an investigation effectively. In legal terms, this may result in a State being unable to fulfil its obligation to investigate under human rights law and IHL, which in turn may cause its international responsibility to be engaged under such bodies of law. When an agreement specifically regulating the authority to investigate or the obligation to cooperate exists, the investigating TCS may pretend from another actor ‒ be it the host State, the leading international organization, or another TCS ‒ the performance of a legal duty. The question then is whether the duty to investigate under human rights law and IHL might entail an obligation on TCSs to arrange these types of agreements.

1. An Obligation to Seek Investigative Cooperation?

In general, the principle of effectiveness and the corresponding standards perform a twofold task: providing guidance on how to conduct an investigation; and functioning as a yardstick to assess a posteriori whether an investigation has been conducted effectively. In this second perspective, the duty to investigate presents a retrospective dimension: effectiveness is employed to evaluate an investigation that has already been conducted. In a different vein, exploring whether a State must also regulate investigative cooperation means to consider a possible prospective dimension of the obligation to investigate. When deciding to contribute troops to a peace operation, a State’s competent authorities are or should be aware of a number of factors: first, the general limitations on the extraterritorial exercise of enforcement jurisdiction; second, and consequently, the necessity of the host State’s consent to carry out certain investigative activities; third, mission-specific SOFAs and contribution agreements might not regulate, or not to a sufficient degree, investigative cooperation with the other actors involved in a peace operation; fourth, the existence of an obligation requiring States, in all circumstances, to take ‘all reasonable steps’ or ‘all feasible measures’ to investigate as effectively as possible.

In the present author’s view, a combined analysis of all these factors is warranted; in particular, it is necessary to read the first three factors in light of the fourth – the ‘all reasonable steps/all feasible measures’ test. What the analysis intends to put forward is an interpretation de lege ferenda, according to which sending States have an obligation to do everything ‘reasonable’ or ‘feasible’ to ensure that agreements regulating investigative cooperation be in place in a peace operation. This would entail for States to arrange such agreements or, at the very least, attempt to influence their negotiation by the international organization that leads a peace operation. As
142 M. Zwanenburg, Accountability of Peace Support Operations (Leiden, Martinus Neijhoff, 2005), p. 291. No such agreements are mentioned in the literature or may be found on NATO’s website. The present author also consulted a NATO legal adviser and an expert in the matter, who in private correspondence stated that, to their knowledge, no participation agreement is adopted in NATO operations. The remainder of the study will thus work on the assumption that such agreements do not exist. Back

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shortly shown, this interpretation is reinforced by existing duties under both human rights law and IHL.

The duty to investigate is a positive obligation prescribing on States a duty to act; it is also a typical obligation of means, which is closely connected to the legal principle of due diligence. Among other things, 143 due diligence is construed as an international standard requiring a State to abide by a certain level or model of conduct determined by a specific norm of international law. 144 The content of such a standard varies according to the specific norm at hand, meaning that the evaluation of a State’s compliance with due diligence will depend on the circumstances and context in which this is applied. 145 In relation to the duty to investigate, such assessment is made in light of the principle of effectiveness. This means that a State will abide by the due diligence standard if it endeavours at its best to do everything feasible to ascertain the facts surrounding a human rights violation and identify those responsible. 146 In peace operations, due diligence will be measured against the background of the ‘all reasonable steps/all feasible measures’ test.

As far as investigative cooperation is concerned, one may argue that a State should seek the cooperation of another State as part of the ‘reasonable’ or ‘feasible’ steps that are necessary to conduct an investigation effectively. This interpretation is reinforced by the existence under human rights law of a duty of inter-State cooperation connected to the obligation to investigate. Human rights instruments and jurisprudence make specific reference to a duty to cooperate between States in the investigation of torture, enforced disappearances, and extrajudicial killings. With almost identical language, the UNCAT and UNCED prescribe that States shall assist each other when investigating allegations of torture and enforced disappearance, including by supplying necessary evidence. 147 Soft law instruments reiterate the existence of such a duty of cooperation. 148 In very clear terms, the Minnesota Protocol provides: “Depending on the circumstances, States [...] have a duty to cooperate internationally in investigations of potentially unlawful death, in particular when it concerns an alleged international crime such as extrajudicial execution”. 149 Certain human rights bodies have given additional support to the view that, when serious human rights violations are at stake, third States are supposed to cooperate with the investigating State by providing all necessary assistance the latter may need. 150 States are thus obliged to seek cooperation, and correspondingly to cooperate when so requested, with regard to investigations into torture, enforced disappearances, and extrajudicial killings as far as they are parties to the UNCAT and the UNCED or treaty and soft law provisions have attained customary status.
143 On the complex and multifaceted topic of due diligence, see R. Pisillo-Mazzeschi, “Due diligence” e Responsabilità Internazionale degli Stati (Milano, Giuffrè, 1989); T. Koivurova, ‘Due Diligence’ Max Planck Encyclopedia of Public International Law, 2010; J. Kulesza, Due Diligence in International Law (Leiden/Boston, Brill Nijhoff, 2016). Due diligence is a customary norm of international law; ICJ, Pulp Mills on the River Uruguay (Argentina v. Uruguay) , ICJ Reports 2010, 14, § 101. Back
144 V.P. Tzevelekos, ‘In Search of Alternative Solutions: Can the State of Origin Be Held Internationally Responsible for Investors’ Human Rights Abuses that Are Not Attributable to It?’, Vol. 35 Brooklyn Journal of International Law 2010, pp. 179‒180. Back
145 Id. , p. 180. Back
146 IACtHR, Velasquez Rodriguez, supra note 15, §§ 176‒177. See above Section II. Back
147 UNCAT, Art. 9; UNCED, Art. 14. These provisions clarify that investigative cooperation remains subject to any relevant domestic law and/or bilateral agreement regulating mutual legal assistance. Back
148 Principles on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions, supra note 19, Principle 8; Basic Principles and Guidelines on the Right to a Remedy and Reparation, supra note 15, Principle III, § 4. Back
149 Minnesota Protocol, supra note 26, § 9. Back
150 IACtHR, Goiburú et al. v. Paraguay, 22 September 2006, Series C No. 153, §131; La Cantuta v. Peru, 29 November 2006, Series C No. 162, § 160; Anzualdo Castro v. Peru, 22 September 2009, Series C No. 202, § 125; HRC, General Comment 31, supra note 15, § 18. See also HRC, General Comment 36, supra note 15, § 28: “States should support and cooperate in good faith with international mechanisms of investigation and prosecutions addressing possible violations of article 6 [of the ICCPR]”. Back

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A duty to cooperate in investigations may even be derived under IHL, specifically from the obligation to ensure respect for IHL enshrined in Common Art. 1 of the GCs ‒ a provision also entailing a due diligence standard. 151 Under Common Art. 1, parties to the conflict have a positive obligation to ensure that members of their armed forces, as well as persons or groups acting under their direction or control, comply with IHL. 152 The obligation to ensure respect further implies that investigation and prosecution be undertaken as a specific means to enforce IHL. 153 As discussed above, IHL requires that war crimes investigations abide by the principle of effectiveness, a duty the fulfilment of which is subject to the due diligence standard encapsulated in Common Art. 1. This may apply to investigative cooperation as well: whenever needed, the investigating State should endeavour at its best to seek cooperation from other relevant actors, as much as this is feasible in light of the concrete circumstances. 154 Third States and international organizations will in turn be required to cooperate in light of their due diligence obligation, also flowing from Common Art. 1 of the GCs, to ensure respect for IHL by actors involved in an armed conflict over which they exert a certain influence. 155

In light of the foregoing it can be argued that, as a matter of lex ferenda, the duty to investigate in peace operations may require TCSs to regulate investigative cooperation in relevant agreements, such as SOFAs and MOUs, as a ‘reasonable’ or ‘feasible’ measure that aims to remove obstacles to the conduct of effective investigations. This would translate into a duty to arrange such agreements or attempt to influence their negotiation by the international organization that leads a peace operation prior to deployment or, thereafter, at the earliest possible stage.

It should be noted that such negotiations might fail or the counterpart, be it the host State, the international organization or a TCS, might refuse to enter into such an agreement. As far as these actors are concerned, their international responsibility may be engaged under the above-mentioned human rights and IHL norms prescribing to cooperate in relevant investigations. The sending State, on the other hand, should consider whether refusing to take part in such an operation or whether assuming the risk of participating without proper agreements in place. In the latter scenario a TCS would have to accept that, in the impossibility of conducting effective investigations for lack of investigative cooperation, its international responsibility might be engaged, especially if a case is brought before a human rights body. 156

In case such cooperation agreements are concluded, to what extent may they prevent the responsibility of an investigating TCS to be triggered under international law? The mere existence of an agreement regulating investigative cooperation might not be sufficient to discharge a State’s duty to investigate under human rights law. It is indeed necessary that all the actors involved in an investigation comply with the standards of effectiveness so that the investigation may overall be considered effective, and the investigating TCS’s obligation may be deemed fulfilled. In the Jaloud case, for instance, the Iraqi authorities had not refused to carry out the autopsy on the victim’s body but rather to allow Dutch investigators to attend it, which the ECtHR considered one of the elements determining the ineffectiveness of the investigation under scrutiny. 157 This shows that the establishment of an obligation to cooperate
151 International Law Association, Study Group on Due Diligence in International Law, First Report, 7 March 2014, p. 12. Back
152 J. Pictet (ed.), Geneva Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field: Commentary (Geneva, ICRC, 1952), pp. 25–26. Back
153 Cohen & Shany, supra note 39, p. 44. Back
154 On the complexities of investigations in the context of coalition operations, see C. Jenks, ‘Coalition Operations and the Obligation to Investigate IHL Violations’, Intercross Blog, 28 September 2016, http://intercrossblog.icrc.org/blog/2016-joint-series-on-international-law-and-armed-conflict-chris-jenks-on-coalition-operations-the-obligation-to-investigate-ihl-violations. Back
155 ICJ, Wall, supra note 22, § 160; ICRC, 2016 Commentary to GC I, Art. 1, https://ihl-databases.icrc.org/applic/ihl/ihl.nsf/INTRO/365?OpenDocument , §§ 138–142, 153–156, 164–173. Back
156 This corresponds to what is happening at present; see ECtHR, Jaloud, supra note 24, §§ 212–216. Back
157 Id. Back

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between a TCS and the other actors involved in a peace operation may in itself not suffice, since the former must also make sure that the latter abide by the standards of effectiveness.

In the present author’s opinion, the duty to investigate should imply, in light of the proposed interpretation de lege ferenda, an obligation on TCSs to ensure that investigative cooperation agreements address the necessity for the host State, international organizations and TCSs to investigate in accordance with the required standards of effectiveness. In this respect, an investigating TCS will have fulfilled its relevant obligations only when all the actors involved in an investigation comply with the standards of effectiveness prescribed by human rights law. If these conditions are not met, such a State will remain liable under international law for failure to investigate effectively. A TCS, in fact, cannot use cooperation agreements as a fig leaf to avoid investigating effectively human rights violations and war crimes.

The following sections will apply the proposed interpretation to the three actors an investigating TCS must or may interact with in a peace operation: the host State, the leading international organization, and other TCSs.

2. The Host State

A clause regulating investigative cooperation between a TCS and the host State, and included in a mission-specific SOFA, should entitle the former to claim a legal duty to cooperate vis-à-vis the latter. The ultimate purpose would be to secure, to the maximum extent possible, that a sending State has the capacity to investigate effectively any alleged human rights violation or war crime committed by its armed forces in the context of a peace operation. A TCS’s possible obligation to regulate investigative cooperation will be shaped according to the circumstances characterising a specific deployment. In this respect, the feasibility for a TCS to negotiate or influence the negotiation of a SOFA cannot be determined in the abstract and must be considered in light of the structure of an operation and the actors involved therein.

With reference to UN operations, the UN Model SOFA already establishes a mutual obligation between the UN and the host State to cooperate in investigations. This encompasses a duty of the host State to provide its authorisation, save in special circumstances, to investigative activities conducted by TCSs. Since the UN Model SOFA does not instead apply to non-UN forces supporting a UN operation, a non-UN-commanded TCS is supposed to adopt a distinct SOFA with the host State. In that case, according to the proposed interpretation de lege ferenda, such sending State would have an obligation to do everything feasible in order to ensure that investigative cooperation be regulated by the SOFA arranged with the host State. With regard to NATO operations, where NATO is in charge of concluding the relevant mission-specific SOFA, TCSs could either endeavour to ensure that NATO negotiates a clause regulating investigative cooperation with the host State or arrange a supplementary agreement with the host State. The latter alternative may be preferable if a sending State is not in a position to influence NATO with respect to the negotiation of the mission-specific SOFA.

As mentioned above, to avoid liability under human rights law an investigating TCS should ensure that SOFAs address the necessity for the host State to investigate in accordance with the required standards of effectiveness. 158 It is difficult to envisage in abstract terms what exact practical application this obligation may have because diverse activities warrant different standards of assessment: ballistic analyses differ from forensic examinations, and both differ from the questioning of witnesses. As a way of example, TCSs may be allowed to monitoring, to a certain extent, the host State’s investigative activities (e.g. attending autopsies), or the latter may be required to provide detailed reports concerning technical analyses. In this respect, existing treaties on mutual cooperation in criminal matters may constitute a point of
158 In this respect, it is worth noting that the host State will be under its own obligation to conduct an investigation effectively, and a failure in this sense will result in an autonomous breach of its legal obligations under international law. Back

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reference. 159 At any rate, the relevant point is that a TCS would be required to ensure that the host State be under an obligation both to cooperate fully in investigations and to adhere to the standards of effectiveness.

3. International Organizations

Whereas an investigating TCS always needs assistance from the host State, it might necessitate the cooperation of the leading international organization. The degree and forms of collaboration will once again vary depending on the structure of an operation. While in UN operations the matter is regulated by the UN Model MOU, no equivalent agreement is usually concluded in UN operations supported by non-UN forces and in NATO operations. To this author’s knowledge, the UN and the supporting TCS do not adopt agreements regulating their relationships, 160 which means that, differently to UN-commanded TCSs, the supporting TCS cannot invoke a legal obligation to cooperate vs-à-vis the UN. In light of the interpretation de lege ferenda proposed above, the obligation to investigate may entail for TCSs a duty to arrange an agreement with the UN regulating investigative cooperation. In this respect, the UN Model MOU may be a point of reference in light of which such an agreement could be designed. It is worth noting that a panel appointed by the UN Secretary-General put forward a similar proposal. 161

It should further be observed that the way the UN conducts investigations is also germane to the fulfilment by a sending State of its obligation to investigate. The UN has indeed the authority to conduct investigations under specific circumstances: it may carry out preliminary fact-finding inquiries aimed at preserving evidence or, when the relevant TCS is unwilling or unable to investigate, administrative investigations into alleged serious misconduct. 162 Being administrative in nature, UN investigations are not necessarily supposed to follow the same standards criminal investigations must adhere to. At the same time, TCSs should be capable of using a UN investigation’s findings within domestic proceedings; this will likely require the UN to follow the standards of effectiveness while investigating. Such an issue was raised in the Zeid Report, which evaluated the possible strategies to tackle the problem of sexual exploitation and abuse in UN operations. 163 In this respect, it is important to highlight that the Office of Internal Oversight Services (OIOS), the competent UN investigative body, in principle adheres to standards that reflect those prescribed by human rights law. 164

An important aspect that the UN Model MOU does not directly deal with is the potential impact of immunities of UN officials on TCSs’ investigations. As the MINUSCA case demonstrates, waiving immunity may prove essential to the effective conduct of an investigation. 165 The UN
159 Inter-American Convention on Mutual Assistance in Criminal Matters, 23 May 1992; European Convention on Mutual Assistance in Criminal Matters, 20 April 1959. Back
160 See above Section VI 2. Back
161 Deschamps, Jallow & Sooka, supra note 3, pp. 85‒86, 88‒89. Back
162 UN Model MOU, supra note 99, §§ 7.12‒7.13. “Preliminary fact-finding inquiry means the preservation of evidence necessary to ensure that a national or United Nations investigation can be successfully carried out at a later stage. While this inquiry may involve the collection of written statements, it will not normally include the interviewing of witnesses or other involved persons”; id. , Annex F, § 29. Back
163 Zeid Report, supra note 3, § 28: “[T]roop-contributing countries frequently complain that evidence gathered by mission boards of inquiry and in prior preliminary investigations is either not sufficient under their national law for use in subsequent judicial or court martial proceedings or has not been gathered in a manner required by their law. Frequently the troop-contributing country will not even get the entire board of inquiry documentation because of a United Nations policy of not releasing documents that might be used by third parties to make claims against the Organization”. Back
164 UN OIOS, Investigations Manual, January 2015, pp. 17‒18. OIOS investigations standards are based, among other things, on the Uniform Guidelines for Investigations, which provide that investigators “shall maintain objectivity, impartiality and fairness throughout the investigative process […], perform [their] duties independently [and] conduct the investigation expeditiously”; see Uniform Guidelines for Investigations, 10th Conference of International Investigators, Jordan, 10‒12 June 2009, §§ 3, 10. Back
165 See above Section IV. Back

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Convention on Privileges and Immunities grants UN officials and experts on mission immunity from legal proceedings, 166 and the UN Model SOFA reiterates such immunities in the context of UN operations. 167 Persons falling under the scope of this Convention can neither be criminally prosecuted for acts performed in the execution of their functions, nor be obliged to cooperate in investigations, testify, or hand over evidence. 168 While this may clearly constitute an impediment for a TCS to conduct an investigation effectively, the UN Convention on Privileges and Immunities also establishes that the UN Secretary-General has the right and the duty to waive immunities if these impede the course of justice and the waiver does not compromise the interests of the UN. 169 In this respect, the Convention provides that: “The United Nations shall cooperate at all times with the appropriate authorities of Members to facilitate the proper administration of justice […] and prevent the occurrence of any abuse in connection with the privileges, immunities and facilities mentioned in this Article”. 170 Additionally, the UN Model MOU imposes on the UN an obligation to cooperate fully with an investigating TCS. 171 As has rightly been suggested, while the UN necessarily retains the prerogative not to waive immunities, it should adopt an approach that presumes cooperation and active participation of UN officials and experts in relevant domestic legal proceedings. 172

Differently from the UN, NATO does not employ participation agreements to govern its legal relationship with TCSs, which constitutes a shortcoming that may impinge on a TCS’s ability to conduct an investigation. 173 In particular, this may concern the essential liaison role that NATO is meant to play with the host State, both when it is the party to the mission-specific SOFA, e.g. in IFOR and RS, or even if the ad hoc operation is the party to it, e.g. in ISAF. In light of the proposed interpretation de lege ferenda, TCSs would bear a duty to arrange agreements that (a) regulate investigative cooperation with NATO, similarly to the case of UN operations supported by non-UN forces, and (b) ensure that any investigations conducted by NATO be in line with the international standards of effectiveness. 174

It should further be pointed out that NATO adopted an agreement governing privileges and immunities, akin to the corresponding UN Convention on Privileges and Immunities, which grants NATO officials and experts on mission immunity from legal proceedings. 175 Like the UN Convention, such an agreement provides that NATO has a right and a duty to waive immunity in the interest of justice and to prevent abuses thereof, as well as an obligation to cooperate with Member States in that regard. 176 Similarly to what has been observed with regard to the UN, it would be desirable for NATO to adopt an approach to immunity based on cooperation and participation of NATO personnel in a TCS’s investigations and legal proceedings.
166 Convention on the Privileges and Immunities of the UN, supra note 93, Arts. V‒VI. For an analysis of the immunities accorded to the various categories of international civil servants, see Hampson, supra note 108, §§ 19‒22. Back
167 UN Model SOFA, supra note 98, §§ 24‒26, 28. Back
168 Code Blue, Fact Sheet: Privileges and Immunities of the UN, 13 May 2015, http://www.codebluecampaign.com/primer-privileges-and-immunities-of-the-united-nations/. Back
169 Convention on the Privileges and Immunities of the UN, supra note 93, Sections 20, 23. Back
170 Id. , Section 21. Back
171 UN Model MOU, supra note 99, § 7.16. Back
172 Deschamps, Jallow & Sooka, supra note 95, p. 91. Back
173 See above Section VI 3. Back
174 In this respect, NATO may adopt standards and procedures of investigations similar to those employed by the UN OIOS; see above note 164. Back
175 Agreement on the status of the North Atlantic Treaty Organization, National Representatives and International Staff, Ottawa, 20 September 1951, Arts. XVIII, XXI. Back
176 Id. , Arts. III, XXII. Back

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4. Troop-Contributing States

Investigative cooperation between TCSs is likely to concern the use of specialised equipment or the participation of military personnel in relevant proceedings. 177 The lack of cooperation by a TCS may in principle hamper another TCS’s ability to conduct an effective investigation. In UN operations, the UN Model MOU provides that the Organization should liaise between the investigating TCS and other TCSs; 178 yet, it does not establish on the latter an obligation to cooperate. Additionally, to this author’s knowledge, TCSs do not adopt separate agreements between each other regarding investigative cooperation either in UN-led or NATO-led operations.

Interestingly, the UN Model MOU regulates the use of a TCS’s equipment by another TCS. Under the section concerning liability for damage caused by a TCS that employed another TCS’s equipment, the UN Model MOU establishes that:
Major equipment can be provided to the United Nations by one troop/police contributor to be used, at the request of the United Nations, by another troop/police contributor. In these cases, the following principles will apply: (a) Adequate training is necessary to ensure that a user is qualified to operate unique major equipment such as armoured personnel carriers. The United Nations will be responsible for ensuring that this training is conducted and to provide funding for the training. The arrangements to provide and conduct this training are to be negotiated between the United Nations, the troop/police contributor providing the major equipment and the troop/police contributor using the major equipment. The results of the negotiation are to be reflected in the respective MOUs. 179
This provision may work as a model for the conclusion of agreements concerning the use of specific equipment for investigation purposes. Such a clause also shows that it is already envisaged that a TCS might be in need of another TCS’s equipment.

Clearly, there is no reason why this kind of agreements may cover major equipment, such as armoured vehicles, and not specialised investigative or forensic equipment. According to the above provision, TCSs are supposed to negotiate ad hoc arrangements concerning training in the use of major equipment, the result of which is to be reflected in the respective MOU. This means that the possibility for a TCS to arrange separate agreements with the UN and/or other TCSs is already a reality within the framework established by the UN Model MOU. With regard to UN operations supported by non-UN forces and NATO operations, it is submitted that, according to the proposed interpretation de lege ferenda, a duty may exist to regulate investigative cooperation between non-UN forces and UN-commanded TCSs, and between TCSs participating in NATO operations, respectively. As discussed, to avoid liability under international law an investigating TCS will have to make sure that other TCSs participating in an investigation follow the standards of effectiveness prescribed by human rights law.

It should be noted that TCSs may be parties to bilateral or multilateral mutual legal assistance agreements, 180 which generally provide for the exchange of evidence and information in criminal and related matters between the investigating State and a third State. If the scope of any such treaty covers investigative cooperation in the context of peace operations, the gaps noted above may be filled, even though this would only concern the relationship between those TCSs that are parties to these agreements.

VIII. Conclusion

In peace operations, the fulfilment of the obligation to investigate may depend on the cooperation established between the actors involved therein. Sending States need the cooperation of the host State for a whole range of investigative activities, and might also
177 The present author is unaware of cases regarding investigative cooperation between TCSs in peace operations. The analysis therefore proceeds on the basis of hypotheses. Back
178 UN Model MOU, supra note 99, § 7.17. Back
179 Id. , Annex B, § 24(a). Back
180 See above note 159. Back

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necessitate the collaboration of the leading international organization or other TCSs. This means that the action or inaction of other entities may affect the ability of a sending State to investigate effectively. A major problem in that regard is the generalised absence of agreements regulating investigative cooperation outside UN-led operations. The UN Model SOFA and MOU contain specific provisions governing investigative cooperation between the UN, the host State, and TCSs. Yet, these agreements do not apply to non-UN forces or to UN-authorised peace operations, such as NATO-led ones.

The present author proposed to construe the obligation to investigate as encompassing a duty to regulate investigative cooperation. This interpretation de lege ferenda was based on the ‘all reasonable steps/all feasible measures’ test, which has emerged from human rights bodies’ jurisprudence and concerns the application of the standards of effectiveness to investigations conducted in difficult security conditions, including peace operations and armed conflict. According to this interpretation, a TCS would be under a duty make its best efforts to ensure that relevant SOFAs and contribution agreements regulate investigative cooperation with the host State, the leading international organization, and other TCSs. Depending on the structure of an operation, this ancillary obligation would require a State either to arrange agreements regulating investigative cooperation or to attempt influencing negotiations of SOFAs and contribution agreements to this purpose. These agreements would have the effect of making investigative cooperation a legal duty for the actors that participate in a peace operation, with a view to preventing to the maximum extent possible that non-cooperation be an impediment to effective investigations.

On a final note, it is worth observing that regulating investigative cooperation through ad hoc agreements, or specific clauses included in SOFAs and MOUs, would face significant legal, operational, and political challenges; not least in light of the different investigative methodologies and techniques applied by States, as well as the differentiated international treaty obligations TCSs may be subject to, which render cooperation in this context particularly complicated. However, the obligation to conduct investigations effectively should remain the primary benchmark guiding State action in this domain, even when fulfilling this duty implies extra efforts on the part of sending States.


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