The Prosecution Challenges of Travelers to the Islamic State

Children cross through an opening in a fence at al-Hol camp that houses some 60,000 refugees, including families and supporters of the Islamic State group, many of them foreign nationals, in Hasakeh province, Syria, on May 1, 2021. (AP Photo/Baderkhan Ahmad)

Since the 2017 collapse of the so-called Islamic State of Iraq and Syria (ISIS), the Syrian Democratic Forces has retained custody of approximately 2,000 foreign terrorist fighters and close to 10,000 Islamic State militants. Despite the professed inability of the Syrian Democratic Forces (SDF) to assume long-term responsibility for the detainees, coupled with repeated requests by the United States, a majority of western governments remain reluctant or unwilling to repatriate them.

The SDF-run makeshift courts, along with discussions on the possibility of setting up an international court in the region (though with no enforceability of the rulings and absent a mandate from the United Nations or consent from the Iraqi or Syrian government), add further complexity to the already diffuse policy stances by the international community on the issue of prosecution. Recent developments like efforts by Iraq’s Kurdish Parliament to prosecute accused ISIS members housed inside Iraq and beyond are adding to the challenge.

Absent international legal mechanisms and multilateral agreements to support the trial of ISIS detainees in northern Syria—including a resolution to adjudicate international crimes—domestic courts in member states are emerging as promising platforms for administering justice. This includes efforts to prosecute international crimes, such as in the case of a female ISIS returnee facing charges against humanity in Germany and an ISIS militant facing charges for war crimes in the Netherlands. However, there are prosecutorial barriers.

The most recent collaborative trends among United Nations (UN) member states seem to focus on reshaping transnational jurisprudence as well as identifying schemes that could potentially inform the work of domestic courts by means of “battlefield evidence.” In 2016, the UN General Assembly established the International, Impartial, and Impartial Mechanism (IIIM) with the stated purpose of “collecting and analyzing evidence of international crimes committed in Syria to assist criminal proceedings in national, regional or international courts or tribunals that have or may in the future have jurisdiction over these crimes.”

The UN Investigative Team to Promote Accountability for Crimes Committed by Da’esh/ISIL (UNITAD) was also recently established, which has to date provided evidence for dozens of domestic trials in several countries. (UNITAD uses the handles Da’esh or ISIL for ISIS). With its mandate extended until September 2021, and at the request of the Iraqi government, UNITAD will likely continue to serve as an important UN mechanism for enhancing Iraq’s investigative and legal capacities, supporting digitalization of evidence related to ISIS crimes in Iraq, and assisting member states in need of evidence for domestic prosecutions, including advancing charges that amount to war crimes and genocide.

Absent a clear path from investigation to prosecution by means of collaboration and information sharing among member states, the mere establishment of mechanisms to collect and preserve evidence does not inevitably translate to successful prosecutions. The fact that evidence gathering is carried out by a UN-led organization and not a state actor has also been cited as a divisive issue.  UNITAD’s role has also been challenged on its inability to meet the requirements of “reliability and transparency,” specifically as it pertains to witness testimony.

Case in point: Despite UNITAD’s contributions, in the way of witnesses and other evidence in support of the case, in 2020, Finland’s Court of Appeal dismissed all charges against two Iraqi men accused of partaking in the “Camp Speicher” massacre of June 2014, where over a thousand Iraqi men were killed by ISIS. The anonymity of witnesses, in particular, presented a prosecutorial headache in this trial, leading to the dismissal of all charges, and prompting needed discussions over the transparency and reliability required for prosecutions, as well as the utility of restrictions on the anonymity of witness testimonies for prosecution purposes.

The UN’s Counter-Terrorism Executive Directorate (CTED) also released its “Guidelines to Facilitate the Use and Admissibility as Evidence in National Criminal Courts of Information Collected, Handled, Preserved and Shared by the Military to Prosecute Terrorist Offences.” The guidelines set out criteria for evidence admissibility in member states’ national criminal proceedings, though often criticized for its non-binding legal gloss and lack of normative appeal. While no direct references were made to information sharing and evidence collection in the context of foreign terrorist fighters (FTFs) who are currently under the custody of the SDF, the guidelines allude to possible alternatives to overcome challenges in evidence collection in “conflict, post-conflict, and high-risk.

In circumstances where the military, in addition to UNITAD, may facilitate evidence collection, this has been relegated to a secondary function, given the difficulties in establishing and meeting legal thresholds for the admissibility of such evidence in domestic criminal proceedings, as is required under SCR 2396. Disagreements among UN Security Council (UNSC) members remain apparent with regard to evidence collected by the military, including in relation to “battlefield evidence” nomenclature, with the US specifically urging members states to develop adequate domestic legal measures and frameworks, in conformity with their respective criminal law, to allow for the admissibility of such evidence in civilian courts.

Given that only a few member states have the necessary capabilities and experience in handling evidence collected in conflict zones, Syria and Iraq included, possible immediate solutions may involve making such information available to member state partners. This was seen in recent US efforts to increase the availability of battlefield evidence in both European Union (EU) and non-EU member states by providing travel records and other material evidence. Further recommendations may include sustained member state training in handling and securing the evidentiary chain of custody, fair trial principles, and fair admission of evidence provided by the military. Some prosecutors and law enforcement entities among the UN member states also see a value in opening more frequent and more direct lines of communication with the military for the purpose of communicating their evidentiary needs vis-à-vis pending and future investigations.[i]

Aside from some instances of documentation provided by nongovernmental organizations and the testimony of asylum seekers, in a complicated political landscape such as Syria, the legal modalities of cooperation and information exchange between the member states and the SDF on matters related to FTFs remain vague, indirect or perplexing, mostly implied and rarely expressed. In conformity with their respective national laws and regulations, many countries remain reluctant to engage directly with the SDF. Given that evidence collection and information sharing among member states is guided by the Mutual Legal Assistance (MLA), prospects for judicial engagement with the SDF, a nonstate actor, on the basis of judicial cooperation rooted in the principle of reciprocity remains a far-fetched notion. Some are cautiously considering and approaching the framework of cooperation, wanting to avoid political and legal backlash at home, and to stay clear of actions that could be seen as legitimizing the SDF.

A handful of countries, however, have been transparent about the nature of their cooperation with the SDF on the matters of prosecution and repatriation. Some countries such as Uzbekistan, Kazakhstan, Russia, and Kosovo have legislated policies that mandate repatriation and prosecution of their nationals upon return from Syria or Iraq. Others have underscored the responsibility to act while also stressing political and technical obstacles and wielding repatriation terms to various effects.

For instance, while amenable to the fact that German citizens who have fought or lived under the so-called Islamic State have the right to return, German authorities have often cited the lack of “state and consular access” in the autonomous region of Syria as the main impediments to legal cooperation and repatriation. Technical objections are also often expressed in the form of gaps in professional practices for evidence collection and classification and a lack of information-sharing protocols and mechanisms necessary to support any information exchange or coordination among the parties involved.[ii]

In the absence of legal authority and mechanisms to cooperate on evidence collection with the SDF with regard to FTFs, judges, and prosecutors are often left to rely solely on the information received through the border management system (i.e., country entry-exit record), witness statements (i.e., local and fellow travelers to Syria), and logistical, travel-related evidence (i.e., ticket purchase to Turkey). While important, a lack of direct battlefield evidence pointing to terrorism-related crimes while in ISIS has placed significant limits on prosecutorial powers and has shifted focus towards lesser terrorism-related charges and other “preparatory terrorism” offenses instead.[iii]

Lastly, one must also not overlook further advantages and limits of the UN system in supporting the prosecution, rehabilitation, and reintegration (PRR) efforts. For instance, France and the United Kingdom vetoed the August 2020 UNSC resolution calling for mandatory repatriation of FTFs and their family members. Aside from this particular legislative impasse, SCR 2396 and the 2018 addendum to the 2015 Madrid Guiding Principles provide some important guidance with regard to the PRR of FTFs and their accompanying family members.

Specific to matters of prosecution, while Belgium, Germany, and the Netherlands remain among the countries with relative success in prosecuting and sentencing their nationals for crimes in Iraq and Syria, the UN resolutions related to FTFs in Syria and Iraq remain a weak alternative in the context of certain member states that lack readiness in terms of legislative infrastructure or due to incongruities in their domestic legislation. For instance, while trials in “absentia” may have worked in countries such as the Netherlands and Belgium, such a practice may not work in Germany due to the country’s “immediacy principle.” The same can be argued with regard to appeals to settle for shorter sentences during plea bargain deals, which, for instance, may run contrary to the call in SCR 2178 for increased criminalization of terrorism-related offenses.

As a critical mechanism in establishing frameworks for cooperation and providing necessary support structures for implementing and monitoring the implementation of PRR resolutions by member states, the UN system should continue to provide additional guidance and necessary procedural safeguards to member states with regard to prosecution, including promoting “localized” initiatives in conflict or post-conflict zones that contribute to higher evidentiary standards in prosecution. The UN system should also stipulate a clearer basis under which governments are, or can, directly engage with the SDF on important legal matters and evidentiary support for domestic prosecutions.

This article is part of a series on the role of the UN system in preventing violent extremism and countering terrorism (PVE/CT), done in collaboration with the Brian Urquhart Center for Peace Operations.

Ardian Shajkovci, Ph.D. is the Director of American Counterterrorism Targeting and Resilience Institute (ACTRI).  He is a lecturer and CT-P/CVE analyst with field research experience in Syria, Somalia, Iraq, Jordan, Kenya, Central Asia, Western Europe, and the Balkans.

 Allison McDowell-Smith, Ph.D. is the Deputy Director of American Counterterrorism Targeting and Resilience Institute (ACTRI).  She is the Chair of the Undergraduate Criminal Justice and Criminal Psychology Programs, and Assistant Professor of Criminal Justice at Nichols College located in Dudley, MA.



[i] First author interview with Kosovo and Albania prosecutors, May 20-28, 2021, Prishtina, Tirana.
[ii] First author discussion with a French lawyer, Northeast Syria, 2019.
[iii] First author interview with Kosovo and Albania prosecutors, May 20-28, 2021, Prishtina, Tirana.