Detention and prosecution by non-state armed groups

Detentions and prosecutions carried out by non-state armed groups have become an increasingly prominent issue, particularly due to the growing attention being paid to such organisations. While shocking reports of prisoner mistreatment have permeated the media, prohibiting these conducts, which are essential in warfighting and the maintenance of public order, is more harmful than accepting their existence. Among the scholarship, the dominant position regarding detention by non-state armed groups is that international humanitarian law implicitly allows for these operations. The discussion of the authorisation for prosecutions performed by these entities is less developed, the dominant position being that these acts are forbidden. This thesis posits that international humanitarian law neither authorises nor prohibits detentions by these groups. Instead, it leaves to each domestic jurisdiction the regulation of this conduct. This thesis proposes that, rather than being forbidden, or implicitly authorised by international law, prosecutions by non-state armed groups are equally relegated to domestic regulation. As such, instead of being based on an international humanitarian law framework, the procedural and judicial guarantees in detention and prosecution by these groups are a matter of international human rights law. This thesis defends the application of a sliding-scale approach, as proposed by Marco Sassòli, to determine how different non-state armed groups can comply with their legal obligations. This thesis suggests that, while varying in resources and territorial control, most non-state armed groups possess the capacity to comply with core obligations found in the international human rights law regulating these conducts. To comply with these core obligations, different approaches must be adopted, considering already existing practices, as well as solutions stemming from different legal systems worldwide.