Often governments will hold hearings on the topic of war atrocities, and these hearings will feature first person interviews.
ProQuest Congressional (formerly LexisNexis Congressional) Coverage of U.S. Congress; hearings, prints, reports, bills, Congressional Record, CRS Reports, Federal Register, Code of Federal Regulations.
In LexisNexis Academic, you can search International legal materials from the European Union and various British Commonwealth nations by clicking on "International Legal" in the right hand menu.
Access UN is an index to the Official Records of the United Nations. It includes citations to the draft resolutions, meeting records, and the UN Treaty Series. Several thousand full-text UN documents are also included in the database.