Fedorenko was deported to the Soviet Union and later executed. Ivan the Terrible (Treblinka guard) Ivan the Terrible is the nickname given to a notorious guard at the Treblinka extermination camp during the Holocaust, identified as Ivan Marchenko in statements made by other guards. Given that only eyewitnesses attested to Demjanjuk being Ivan the Terrible, whereas documentary evidence seemed to indicate that he had instead been a Sobibor guard of little note, OSI considered dropping the proceeding against Demjanjuk to focus on higher profile cases, however OSI's new director Allan Ryan chose to go ahead with the prosecution of Demjanjuk as Ivan the Terrible. OSI's most notorious prosecution was that of John Demjanjuk who was accused of being "Ivan the Terrible", the gas chamber operator at Treblinka. The moniker alluded to Ivan IV, … The OSI, which handles war crimes, denied the charge and claimed in turn that Demjanjuk’s supporters obtained copies of the documents in question without OSI approval, possibly by stealing them. The OSI was aware he faced execution and was advised by the State Department to relay that information to him but refused to do so.

The OSI did nothing to counter the misperception of Demjanjuk’s role, and in fact, nudged it along by withholding from Demjanjuk’s lawyers the findings of a Polish investigation of the death camps in Poland that there may have been additional Ukrainian guards known to inmates as Ivan the Terrible. An hour with Allan Ryan Jr., who was for four years in charge of the OSI and who prosecuted Linnas and Demjanjuk, yields information relevant to evaluating the OSI's work.