Between April 1992 and December 1995, more than 100,000 people were killed in the war in Bosnia and Herzegovina. The terrible atrocities committed in this period have been much discussed and studied and many prosecuted as acts of genocide, war crimes or crimes against humanity. But so far, the academic scholarship has focused on the role of the military in these events. This has come at the expense of considering the police’s role, which Nielsen here demonstrates as crucial. Nielsen traces the origins of the war in Bosnia and Herzegovina to the police and associated paramilitary groups. Nielsen makes this ground-breaking case by drawing on a host of confidential archival sources, academic research and practical experience as a widely cited expert witness in the most notorious of the war crimes tribunals. His innovative new history sheds light on wider issues regarding the dissolution of Yugoslavia, the Balkan wars and the region today.