John Demjanjuk (born Ivan Mykolaiovych Demjanjuk; Ukrainian: Іван Миколайович Дем'янюк; 3 April 1920 – 17 March 2012) was a Ukrainian-American autoworker accused of war crimes for having allegedly worked as a guard at Nazi extermination camps during World War II. Legal cases surrounding his alleged Nazi collaboration began during the 1970s and continued until his death in 2012.