The report is based on findings from newly-declassified decades-old Army and CIA records released under the Nazi War Crimes Disclosure Act of 1998 (the Act), these records were processed and reviewed by the National Archives-led Nazi War Crimes and Japanese Imperial Government Records Interagency Working Group (IWG), and written by IWG historians Richard Breitman and Norman J.W. Goda.

The report highlights materials opened under the Act, in addition to records that were previously opened but had not been mined by historians and researchers, including records from the Office of Strategic Services (a CIA predecessor), dossiers of the Army Staff’s Intelligence Records of the Investigative Records Repository (IRR), State Department records, and files of the Navy Judge Advocate General.

Hitler’s Shadow augments the IWG’s 2005 final report to Congress, U.S. Intelligence and the Nazis, and includes wartime and postwar US intelligence documents on the search for and prosecution of Nazi war criminals; Allied protection or use of Nazi war criminals; and the postwar activities of war criminals both in the United States and abroad.