Mathias Holvoet is PhD-Researcher in International Criminal Law at the Vrije Universiteit Brussel, Belgium. He is also a member of the Research Group on Fundamental Rights and Constitutionalism (FRC). Dersim Yabasun is a PhD-Researcher in the International and European Law Department, Maastricht University, The Netherlands. On 18 December 2012, Mathieu Ngudjolo Chui (Ngudjolo) - a Congolese militia leader - became…