By Tanya Mehra, Merlina Herbach, Iwa Maulana
According to UNSC 1373(2001), States should bring alleged terrorists to justice, reflecting the seriousness of the crimes they have committed, which forms a vital aspect of an effective counterterrorism strategy. Consequently, States need to ensure that any person who participates in the financing, planning, preparation, or perpetration of terrorist acts or in supporting terrorist acts is brought to justice. States must similarly ensure that such terrorist acts are established as serious criminal offences under domestic law and that the punishment duly reflects the seriousness of such terrorist acts. When committed during armed conflict, some terrorist acts can constitute war crimes, and where terrorist acts are conducted as part of a widespread or systematic attack directed against a civilian population, they can constitute crimes against humanity. In some situations, terrorist acts may also constitute genocide if they are committed with intent to destroy, in whole or in part, a national, ethnic, racial, or religious group. While several terrorist groups such as the Islamic State of Iraq and Syria (ISIS), Boko Horam, Taliban, or the Maute Group are engaged in an armed conflict, one conflict stands out: the conflict in Syria and Iraq. The rise of ISIS resulted in an unprecedented flow of foreigners who travelled to the conflict zone. In response, several United Nations Security Council Resolutions (UNSCRs), in particular 2178(2014) and 2396(2017), oblige States to take measures to prevent such travel and criminalise a range of activities related thereto. Several international independent organisations have documented how ISIS committed attacks against civilians, in particular minorities, pillaged houses, in addition to multiple crimes other crimes such as murder, persecution, enslavement, sexual slavery, and rape. Several of these crimes amount to so-called core international crimes, namely war crimes, crimes against humanity or genocide. Hence, in recent years, several countries have started to prosecute members of ISIS for both terrorist offences and core international crimes. Examples include the prosecution for the war crime of pillaging, where members of a terrorist organisation occupied an estate after the original inhabitants were forced to flee, or for the war crime of outrage upon personal dignity for posting a picture of a mutilated body with degrading comments on social media. By prosecuting terroristrelated acts as core international crimes, perpetrators are being held accountable for the full range of crimes they have committed. This may lead to high(er) sentences and provide justice to victims. Ultimately, prosecuting terrorist-related offences with linkages to core international crimes can strengthen efforts to end impunity. Indonesia has seen a considerable number of its citizens travel to Syria and Iraq to join ISIS and other organisations and, like many other countries, is concerned with the security risks that are involved but also how to adopt effective prosecution, rehabilitation, and reintegration approaches. This report looks at the challenges and opportunities to prosecute alleged terrorists for both terrorism and core international crimes in Indonesia. This report reflects the findings of the project ‘Interlinkages Indonesia’ which was conducted by the International Centre for Counter-Terrorism – The Hague (ICCT) together with the Indonesian Badan Nasional Penanggulangan Terrorisme (BNPT) from 15 June 2023 to 31 March 2025. During this project, two workshops, a closed-door expert meeting ,and a public panel were held. This report reflects the main findings on how cumulative charging for terrorism and core international crimes can be implemented in Indonesia for the so-called foreign terrorist fighters (FTFs), especially in light of the new Indonesian criminal code that will enter into force on 1 January 2026. This report provides a short overview of the status quo concerning Indonesian foreign terrorist fighters and the approach taken thus on prosecuting those that have returned. After discussing some of the legal, institutional, and evidentiary challenges, this report provides an overview of the opportunities for Indonesia to adopt cumulative charging for terrorist offences and core international crimes.
The Hague: The International Centre for Counter-Terrorism (ICCT) , 2025. 30p.