Thirty-four years after the end of World War II, in 1979, the Office of Special Investigations was created in the Justice Department of the United States to find war criminals from countries that had lost wars against the United States, who had moved to the United States and established themselves there.
This article on a DOJ report on war criminals and the effort to locate, try, de-naturalize, and deport people who could be accused of being such a person mentions one of OSI's many failures, that of the prosecution of John Demjanjuk, although the reporter leaves it unstated whether that failure was a failure to convict Demjanjuk or rather having prosecuted him in the first place.
One of the many interesting items in the article is the mention that last March, OSI was folded into the new Human Rights and Special Prosecutions Section after 31 years of scandal-ridden existence higher up in DOJ's vast organization chart. The article contains a link to DOJ's effusively self-congratulatory announcement of this change.
Another link in the article goes to DOJ's own report, which appears (in its whole, unredacted form) to have been purloined somehow by the New York Times. It contains many revelations for those interested in the United States's post-war dealings with the racial policies and war measures of Nazi Germany in World War II.