In 1940, he was drafted into the Red Army. After a battle in Eastern Crimea, he was taken prisoner by the Germans and was held in a camp for Soviet prisoners of war in Chełm. According to German records, Demjanjuk most likely arrived at Trawniki concentration camp to be trained as a camp guard for the Nazis on 13 June 1942. He was assigned to a manorial estate called Okzow on 22 September 1942, but returned to Trawniki on 14 October. He was transferred to Majdanek concentration camp, where he was disciplined on 18 January 1943. He was sent back to Trawniki and on 26 March 1943 he was assigned to Sobibor concentration camp. On 1 October 1943 he was transferred to Flossenbürg, where he served until at least 10 December 1944.