On September 4, 1939, a special bureau was established within the legal department of the Wehrmacht with the task of ‘ascertaining violations of international law committed by enemy military and civilian persons against members of the German armed forces, and investigating whatever accusations foreign countries should make against the Wehrmacht’. The purpose of this article is to provide a brief overview of the material collected by the Germans during the war, to test the credibility of the German investigations, review case-studies and inquire into the integrity of the judges carrying out the investigations. The Wehrmacht bureau functioned from the very beginning until the final days of war. It investigated some 10,000 war crimes, of which the files for perhaps some 4,000 have survived. Half the files contain investigations of war crimes in the Soviet Union; the other volumes refer to war crimes allegedly committed by American, British, French, Polish, Yugoslav and other Allied nationals. After a careful review of the bureau's records and methods of operation, the conclusion is warranted that the investigations were carried out in a methodically correct manner and that many of the reports present prima facie cases that deserve further investigation. There remains thefundamental question of the judges' integrity, how it was possible for them to carry out investigations into Allied war crimes, when the German government, the SS, the Einsatzgruppen and the Wehrmacht were engaging in various degrees of official criminality. In search of an answer, the author reviews the testimony of numerous witnesses at the Nuremberg trials, including SS judge Georg Konrad Morgen, who had the commander of Buchenwald arrested on corruption charges, but was prevented from completing investigations into concentration camp killings. Hitler's order no. I concerning secrecy appears to have been largely observed, thus frustrating investigation attempts and keeping knowledge of the Holocaust relatively limited.