Joint Series on International Law and Armed Conflict: The Obligation to Investigate Violations of IHL

Written by

This is the third post in our joint blog series arising out of the 2016 Transatlantic Workshop on International Law and Armed Conflict.

The author writes in his personal capacity, the views expressed in this post are his own, and not those of the Royal Navy or UK Ministry of Defence.


Understanding the parameters of a state’s obligation to investigate alleged violations of international humanitarian law is crucial to both the legitimacy of armed forces, and their military effectiveness.   If a state was unwilling, or unable, to investigate egregious behaviour by their armed forces this would not only contravene their obligations under the Geneva Conventions it may lead to investigations by the International Criminal Court for those states parties to the Rome Statute, but also attract significant opprobrium.  Equally, in planning military operations, significant resources are often required to properly investigate alleged violations of IHL.  This in turn requires trained personnel in sufficient numbers to perform this function, and robust military doctrine and national legislation to guide it.  This brief paper seeks to explore the extent of the obligation to investigate alleged violations of IHL, what constitutes a ‘compliant’ investigation, and how this requirement interacts with the obligation to investigate in international human rights law.

1. To what extent does LOAC/IHL provide an obligation to investigate alleged violations?

International Armed Conflict

Rule 158 of the International Committee of the Red Cross’s Study on Customary International Law describes the obligation of states to investigate war crimes in the following terms:

States must investigate war crimes allegedly committed by their nationals or armed forces, or on their territory, and, if appropriate, prosecute the suspects. They must also investigate other war crimes over which they have jurisdiction and, if appropriate, prosecute the suspects.

The ICRC Rule 158 is reflected in numerous international instruments and supported by academic opinion. Additionally, the preamble to the Statute of the International Criminal Court recalls “the duty of every State to exercise its criminal jurisdiction over those responsible for international crimes.”  Further, the Turkel Commission convincingly asserts that ‘[…] in relation to the nature of the violations, it can be deduced from the Commentary on the Geneva Conventions that the obligation to investigate and commit for trial the perpetrators of breaches is not limited merely to those grave breaches defined as such in the Conventions, but includes all breaches of international humanitarian law that amount to ‘war crimes.’’  Finally, both the military manuals of numerous states and their practice of investigating alleged violations of IHL, support the ICRC’s assertion made in Rule 158.

Non-international Armed Conflict

Despite the fact that the duty to investigate violations of international humanitarian law is not mentioned in Common Article 3 of the Geneva Conventions, or in the Second Additional Protocol, it is submitted that the obligation also exists in non-international armed conflicts (NIACs).  This assertion is supported by state practice, ICRC Rule 158, and the findings of the Turkel Commission.  The Turkel Commission examined this issue in detail, and in support of their assertion that the obligation to investigate applies equally in a NIACs cited, inter alia, ‘Article 149(3), GC IV (as well as an equivalent provision in the other three Conventions) in that there is an obligation to suppress all acts contrary to the Conventions (including, it may be assumed, acts contrary to Common Article 3); the preamble to the Rome Statute that recognizes a customary duty of States to investigate all crimes under international law, including war crimes committed in non–international armed conflicts; and the statutes for ad hoc tribunals, for example, the International Criminal Tribunal for Rwanda.’  It is further submitted that the type of investigation required and the procedures to be followed are equally applicable to IACs and NIACs.  These procedures can, however, be modified to reflect the circumstances encountered by those responsible for conducting the investigation.

2. Is the obligation only applicable in cases of allegations of war crimes?

A strict interpretation of Rule 158 of the ICRC study, and the findings of the Turkel Commission, might appear to indicate that the obligation to investigate in IHL is only applicable to allegations of war crimes.  This does not, however, accurately reflect either certain state practice or the entire corpus of IHL in this area.  Indeed, the Turkel Commission considered that, ‘Article 146, GC IV, (as well as the other three Geneva Conventions and the First Additional Protocol) imposes a general duty to prevent all violations of international humanitarian law (‘suppress’).  ‘Suppression’ of violations requires States to ensure compliance with international humanitarian law in its entirety and to prevent future violations from being committed or repeated.’  Equally, numerous offences exist within the UK Armed Forces Act 2006, for example, that create an obligation on military commanders to investigate alleged violations in circumstances where the conduct alleged falls short of war crimes, yet adversely affects civilians during armed conflict.  To illustrate, if a UK soldier during armed conflict were to steal a loaf of bread from a civilian this would not amount to a war crime.  This action would, nonetheless, constitute an offence of theft, pursuant to the Armed Forces Act 2006, and be liable for prosecution as well as subject to administrative action, including dismissal from the armed forces.

3. What degree of suspicion of violation will trigger the obligation to investigate?

State practice would appear to indicate that a mere complaint is not sufficient to trigger the obligation to investigate an alleged violation of IHL.  While the terminology used by states vary, a common theme is that the complaint must be ‘reasonable’ or ‘credible’.  The Turkel Commission did, however, further consider that:

Whether a reasonable suspicion of a war crime exists depends on the facts of the concrete event and its particular context. In certain cases, the facts of the matter are sufficient to indicate that the act allegedly committed is ostensibly of a criminal nature and, consequently, an investigation should be commenced immediately. Examples of cases of this kind include alleged violations of absolute prohibitions of international law, such as use of civilians as ‘involuntary human shields’, rape, looting, or a wilful attack against civilians.  The common denominator of these cases is that international law does not recognize any circumstances that justify their occurrence, and therefore credible information suggesting their occurrence in itself gives rise to a reasonable suspicion that a war crime has been committed.

With respect to the origin of the complaint, this is unrestricted and can come from any source, whether it be an individual, next of kin, NGO or member of the public or armed forces.

4. What types of investigations does IHL require and what procedures are to be followed? 

IHL does not provide comprehensive guidance on the ‘practical content’ of investigations.  As a consequence, states have looked to their own criminal law, human rights law, or both, to further elucidate the principles that govern the investigation of an alleged violation of IHL.  There is general agreement that an investigation ought to be independent, impartial, effective and thorough.  The application of the human rights law requirement of transparency to ‘IHL investigations’ is, however, more controversial.  The Turkel Commission, for example, did not discover the requirement of transparency in any IHL sources.

There is general agreement that an ‘IHL investigation’ can be ‘tailored’ or ‘contextual’ to reflect the circumstances existing at the time.  Naturally, it will be considerably more difficult to conduct an independent, impartial, effective and thorough investigation during a period of intense military activity as opposed to a relatively benign military occupation.  The ability to ‘tailor’ an investigation to the circumstances existing at the time is also reflected in international human rights law (see Al-Skeini, para. 165).

5. How do existing practices regarding investigations in the theatre of conflict compare?

The approach of the UK

During armed conflict the UK has a number of mandated procedures designed to comply with the obligation to investigate violations of IHL.  Certain procedures are initiated following the use of lethal force, or other serious incident, irrespective of whether or not a ‘reasonable’ or ‘credible’ allegation of a violation of IHL has been made.  A serious incident report is the first stage in this process and involves the unit involved in, for example, the use of lethal force making a brief report of the circumstances as they perceive them.  Having received the serious incident report, the commander of the battlegroup will have to decide upon one of three possible courses of action, namely:

1. If only positively identified enemy forces have been killed or injured and there is no suggestion of any breach of the Laws of International Armed Conflict (LOAC) or Rules of Engagement (ROE) then no further action will be necessary.

2. If civilians may have been killed or injured although there is no indication that LOAC/ROE have been breached a Shooting Incident Review (SIR) should be initiated.

3. If it appears there may have been a breach of the ROE or LOAC or a friendly fire incident or any other circumstances deemed appropriate then the incident is reported to the Service police.

Taken in isolation, this procedure is beset with legal, procedural and practical difficulties. That said, however, where a ‘reasonable’ or ‘credible’ allegation of a violation of IHL arises the military commander is required, pursuant to the Armed Forces Act 2006, to inform the military police, who in turn are required to investigate.  Recent legislative and structural changes to the administration of the UK military police now provide the requisite degree of independence, thus enabling the conduct of impartial, effective and through investigations.  Naturally, this is subject to the allegation being made in a manner that would facilitate the conduct of a compliant investigation.  For example, the allegation being made contemporaneously would increase the likelihood of the military police being able to conduct an effective investigation.

Where allegations are made some years after the armed conflict has ended, the UK, through for example the Iraq Historic Abuse Team (IHAT), have been willing to investigate these allegations in order to comply with their IHL obligations.  Where the IHAT procedures have been subject to successful legal challenge they have been modified to ensure compliance.  It is significant, however, that these challenges have been brought in respect of the human rights law obligations of the UK and not the state’s IHL obligations to investigate.

6. Does IHL include obligations of transparency?

Transparency can be seen as the requirement for ‘openness, communication and accountability’ in the investigative process.  More specifically, it includes the requirement to ensure the victim, or the victim’s next of kin, are kept apprised of the progress of an investigation and the publication of an investigation report.  The Turkel Commission and academic opinion appear to indicate that there is no ‘explicit recognition’ of the requirement for transparency in respect of an ‘IHL investigation’.  The mere fact that IHL does not require transparency in ‘IHL investigations’ does not mean, however, that there ought not to be.  That said, there are practical difficulties that may fetter, or preclude, such a possibility.  Military operations, by their nature, often involve a degree of secrecy that is necessary to develop, and maintain, a military advantage or protect the identity of individuals.  As such, any report may need to be heavily redacted in order to protect the identity of individuals (for example, special forces operatives), safeguard tactics, capabilities or systems.  The extent to which a report is redacted may significantly reduce its utility.

7. The Interaction between IHL and IHRL.

The recent Court of Appeal judgment in Al-Saadoon and Others v Secretary of State for Defence is the latest in a series of cases examining the UK’s human rights obligations during operations in Iraq from 2003 onwards.  When read in conjunction with Mr. Justice Leggatt’s judgment of the High Court in the same case, it provides some of the most up-to-date developments of human rights law in this area.  The rulings, inter alia, considered the extent of the state’s duty to investigate alleged breaches of article 2 (the right to life) and article 3 (freedom from cruel, inhuman and degrading treatment and torture) of the European Convention on Human Rights.  The issues in respect of jurisdiction are considered here.  The duty to investigate under articles 2 and 3 arises once alleged breaches are “brought to the attention” of relevant state authorities.  In straight-forward cases, the time that has elapsed between the alleged breach and its being reported to authorities is short.  Where allegations are not “brought to the attention” of the state authorities until long after the alleged breach (12 years in some cases from Iraq) it is more likely the claim will be struck out.  Mr. Justice Leggatt took this position even in cases where he considered there was a reasonable excuse for the claimant taking so long to bring allegations to the authorities’ attention.

Each case is to be assessed on its own merits, and the applicable legal framework is determined by the circumstances at the time of, for example, the use of lethal force.  To illustrate, during a period of occupation, IHL would govern the use of lethal force in respect of ‘responding to an attack by insurgents on a military convey’, and a state’s human rights obligations would be considered in light of the applicable IHL.  Alternatively, ‘firing on a car that failed to stop at a checkpoint [would be] covered by human rights law applicable to police operations’.  The applicable legal framework and nature of the incident then, in turn, determine whether a human rights law compliant investigation ought to be conducted.  For example, where an enemy combatant dies during armed conflict there is no requirement to conduct any investigation, unless there is ‘positive evidence’ to suggest that the use of force was unlawful.  Where a civilian dies during armed conflict due to the actions of the state’s armed forces this must be justified, by the state.  One method would be by concluding an IHL compliant investigation – the investigation need not comply with human rights law.  Where, however, human rights law is the applicable legal framework by which the use of lethal force is governed then a human rights law compliant investigation must be undertaken.  For example, the killing of an unarmed civilian by armed forces at a public demonstration during a period of occupation.

The Court of Appeal in Al-Saadoon agreed with Mr Justice Leggatt’s analysis of the obligation to investigate alleged violations of Article 3 ECHR.  The duty of states ‘not to send an individual to another State where there are substantial grounds for believing that he would face a real risk of being subjected to torture or other prohibited treatment’ (the Soering obligation) was considered in detail by the Court.  In sum, the Court concluded that not all ‘Soering-type’ cases created an investigative obligation on States.  In principle, however, ‘cases in which a contracting state perpetrated mistreatment and cases in which a contracting state aided or assisted mistreatment’ would require investigation.

The real impact of Al-Saadoon is not on the ability of military commanders to authorize, or soldiers to use, lethal force during armed conflict.  Nor does it adversely affect the ability of States to transfer detainees during military operations.  Rather, Al-Saadoon, and previous judgments of the ECtHR and domestic courts, create obligations to investigate alleged violations of the right to life during armed conflict, or military occupation, that may be more onerous than those required by IHL.  As a consequence, UK armed forces may be required to train and equip sufficient numbers of independent military investigators to comply with this obligation.


In conclusion, IHL does place an obligation on states to investigate alleged violations.  This obligation undoubtedly encompasses allegations of war crimes, and state practice would indicate that criminal offences not amounting to war crimes are also, in practice, investigated and prosecuted.  A mere complaint is unlikely to trigger the obligation to investigate, rather the complaint must be ‘reasonable’ or ‘credible’.  Once an investigation has been initiated it must be independent, impartial, effective and thorough.  On balance, it is unlikely that an ‘IHL investigation’ must be transparent, as required by international human rights law.  On the basis of recent ECtHR and domestic judgments it is submitted that human rights law is increasingly applicable to the activities of armed forces overseas.  The circumstances in which armed forces operate, for example in the conduct of hostilities or occupation, would not appear to be entirely determinative of the legal framework applicable to either the use of force or the type of investigation (IHL or IHRL compliant) required.  Further analysis of the circumstances in which, for example, lethal force was used would, on the basis of the judgment in Al-Saadoon, appear to be required.

Print Friendly, PDF & Email

Leave a Comment

Comments for this post are closed