The United States, as well, through the Office of Special Investigations (OSI) in the U.S. Department of Justice, has tracked down suspected Nazi offenders. According to American law, U.S. courts do not have jurisdiction to try individuals for crimes committed outside the United States unless the crimes were committed against American citizens. Therefore, OSI litigates against Nazi war criminals for violating U.S. immigration and naturalization laws. In the 21 years since it was created, OSI has investigated hundreds of cases and sought the denaturalization and/or removal from the United States of more than 117 Nazi war criminals. The vast majority have involved Lithuanian, Latvian, Ukrainian, and ethnic German collaborators who emigrated to the United States shortly after the war from displaced persons camps in Germany and Austria. The OSI is still active today.

Simon Wiesenthal (1908-2005), a Holocaust survivor, dedicated his life to raising public awareness on the need to hunt and prosecute Nazis who have evaded justice. After liberation, he worked for the War Crimes Section of the United States Army, and in 1947 he opened the Jewish Historical Documentation Center in Austria. Wiesenthal is credited for exhorting postwar Western governments to locate and prosecute escaped Nazi offenders as well as offering leads that sometimes led to their extradition. Among those about whom Wiesenthal provided leads to war crimes investigators are: Adolf Eichmann, administrator of the “Final Solution”; Franz Stangl, commandant of the Sobibor and Treblinka killing centers; and Karl Silberbauer, the Gestapo agent who led the arrest of Anne Frank and her family. Wiesenthal also provided information that led to the discovery that Hermine Braunsteiner Ryan was residing in New York State. Braunsteiner-Ryan was the first Nazi criminal to be extradited from the U.S.