Ivan the Terrible (born c. 1920) is the nickname given to a notorious guard Ivan Marchenko, at the Treblinka extermination camp during the Holocaust. The moniker alluded to Ivan IV, also known as Ivan the Terrible, the infamous Tsar of Russia. "Ivan the Terrible" gained international recognition from the 1986 John Demjanjuk case; however very little is known about Ivan Marchenko, and he is not mentioned in any early authoritative Holocaust literature. John Demjanjuk was accused first of being Ivan the Terrible at the Treblinka concentration camp, but in 2011 he was accused of war crimes as a different guard named Ivan Demjanjuk who served at the Sobibor extermination camp.