Historian, Harvard and Yale Universities. Doctorate in African history. MacArthur Fellow (1999). Researcher on the Great Lakes region of Africa for Human Rights Watch, Senior Adviser Africa division of HRW. Expert witness to the International Criminal Tribunal for Rwanda, providing evidence to judicial authorities in Belgium, Switzerland, Canada, and the U.S. Assisted the U.N. commission, the OAU commission, the Belgian Senate, and the French National Assembly in their investigations of the Rwandan genocide. Co-chair of the 1993 International Commission of Investigation into Human Rights Abuse in Rwanda. Chairperson of 1994 International Commission, investigating the mass killings in Burundi.

Publications include: Scholarly articles and monographs on Rwandan history; Leave None to tell the Story: Genocide in Rwanda, (Receiver of the Lemkin Award of the Association of Genocide Scholars, 2000–2001).