I study perpetrators and perpetration of mass violence, irregular armed forces, and judicial responses to mass violence. I have published a number of chapters, articles, and a monograph. My PhD, focusing on Serbian paramilitaries during the breakup of Yugoslavia, was based on primary documents and research in the archives of the International Criminal Tribunal for the former Yugoslavia in The Hague. I remain interested in, and conduct research on, criminal proceedings in cases of genocide, crimes against humanity and war crimes. Recently, I have been particularly interested in justice options for Ukraine.