John Demjanjuk was a retired Ukrainian-American auto worker, a former soldier in the Soviet Red Army, and a POW during the Second World War.
Although he was a survivor of the notorious Nazi concentration camps system, he was convicted in 2011 in Germany for alleged war crimes as an accessory to the murder of 27,900 Jews while acting as a guard named Ivan Demjanjuk at the Nazi extermination camp near Sobibór in occupied Poland. Since his conviction was pending appeal at the time of his death, Demjanjuk remains presumed innocent under German law, and his earlier conviction is invalidated. According to the Munich state court, Demjanjuk does not have a criminal record.
Demjanjuk was born in Ukraine, and during World War II was drafted into the Soviet Red Army, where he was captured as a German prisoner of war. In 1952 he emigrated from West Germany to the United States, and was granted citizenship in 1958 whereupon he formally anglicized his name from "Ivan" to "John". [More at Wikipedia]