Ivan the Terrible ( Treblinka guard ) 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 . Background . Treblinka was operated by 20 to 25 SS Police overseers ( Germans and Austrians ) and 80 to 120 guards of various Soviet ethnicities , including Russian and Ukrainian Red army prisoners of war . They were assisted by a cadre of Jewish inmates known as Kapos , who were prisoner functionaries . The name Ivan was not an uncommon name in the camp . Ivan ( also Iwan in Polish and German ) is a common Ukrainian , Russian and Belarusian given name . Volksdeutsche were known to have Slavic given names . An example would be , Ivan Klatt , a Volksdeutscher who served in the Sobibor extermination camp , as a " Ukrainian guard " leader . According to Rajchman six men called Ivan worked at Treblinka . The vast majority of guards , who were trained at Trawniki concentration camp , were Volksdeutsche , and were valued because they spoke German , Ukrainian , Russian and other languages . They could also understand basic Yiddish . The German and Austrian SS command , local Poles , and Jewish inmates often referred to guards ambiguously as " Ukrainians " either because of their ethnicity , or because they originated from Ukraine . Most of the squad commanders were Volksdeutsche . Duties . Ivan was identified as Ukrainian . His function at the camp was to operate the two tank engines that fed the gas chambers , although there were more guards referred to Ivan the Terrible at Treblinka . He was also known for his extreme cruelty . Holocaust survivor Chil Rajchman reported that Ivan was about 25 years old at the time he worked in the camp . He was known to cut off the ears of workers as they walked by , and these people were forced to continue working as they bled from their severed ear . Shortly after , he would shoot the person . He also tortured victims with pipes , swords and whips before they were killed in the gas chambers . Identity . Ivan ' s true identity was conclusively discovered only in 1990s . In 1970s - 80s John Demjanjuk , a retired suburban Cleveland autoworker of Ukrainian descent , was accused of being Ivan . He was tried in Israel in 1986 and sentenced to death , but the conviction was overturned due to lack of evidence . One remarkable event , during the Israel trial , involved a star witness for the prosecution , Eliyahu Rosenberg . Asked by the prosecution if he recognized Demjanjuk , Rosenberg asked Demjanjuk to remove his glasses " so I can see his eyes . " Rosenberg approached and peered closely at Demjanjuk ' s face . When Demjanjuk smiled and offered his hand , Rosenberg recoiled and shouted " Grozny ! " meaning " Terrible " in Polish and Russian . " Ivan , " Rosenberg said . " I say it unhesitatingly , without the slightest shadow of a doubt . It is Ivan from Treblinka , from the gas chambers , the man I am looking at now . " " I saw his eyes , I saw those murderous eyes , " Rosenberg told the court , glaring at Demjanjuk . Rosenberg then exclaimed directly to Demjanjuk : " How dare you put out your hand , murderer that you are ! " It was later revealed with great embarrassment for the prosecution , that Eliyahu Rosenberg had previously testified in a 1947 deposition that “ Ivan the Terrible ” had been killed during a prisoner uprising . On July 29 , 1993 , the Israeli Supreme Court overturned the guilty verdict on appeal . The ruling was based on new evidence , the written statements of 37 former guards at Treblinka ( some of whom had been executed by the Soviet Union , others died of old age , and could therefore not be cross - examined ) that identified Ivan the Terrible as another man named , Ivan Marchenko ( possibly Marshenko , or Marczenko ) . One document described Ivan the Terrible as having brown hair , hazel eyes , square - faced , and a large scar down to his neck ; ( Demjanjuk was blond with grayish - blue eyes , round - faced , and no such scar . ) According to one testimony , Marchenko was last seen in Yugoslavia in 1944 . According to the testimony of Nikolai Yegorovich Shelayev , a Russian Treblinka gas chamber operator , he and Marchenko together with two Germans and two Jews , operated the motor which produced the exhaust gas which was fed into the chambers of the gas chambers . Shelayev and Marchenko were transferred from Treblinka to Trieste in July 1943 where Marchenko guarded German warehouses and a local prison . In 1944 , as Allied forces approached , Marchenko and a driver named Gregory " fled in an armored car to the partisans in Yugoslavia . " Shelayev last saw Marchenko in the spring of 1945 , in Fiume , where he saw him coming out of a brothel . Marchenko told Shelayev that he had joined the Yugoslav partisans . As late as 1962 , the Soviet authorities were looking for him . The Soviet documents created enough reasonable doubt to disqualify Demjanjuk , and his previous conviction was overturned . Some of the exculpatory evidence that led to Demjanjuk ' s release in 1993 had come to light years before and was deliberately withheld from the Israelis by the Office of Special Investigations ( OSI ) of the US Department of Justice , which had urged Israel to charge him with being Ivan the Terrible . The Honorable Gilbert S . Merritt , Judge of the U . S . Court of Appeals , Sixth Circuit , Chief Judge 1989 - 1996 had this to say about the OSI ' s handling of the Demjanjuk case : " Today we know that they — the OSI , the prosecution in the case and the State Department — lied through their teeth . Even then they knew without a doubt that Demjanjuk was not Ivan the Terrible , but they hid the information from us . I am sorry that I did not have the information at the time . If I did , we would never have ruled in favor of his extradition to Israel . " Merritt claimed that what happened in his courtroom was : " nothing short of a witch hunt . In retrospect , it reminds me of the witch trials in Salem , Massachusetts 300 years ago . The prosecution , counseled by the OSI , presented documents and witnesses whose testimony was based on emotions and hysteria , but not hard evidence . To my regret , we believed them . This instance is a prime example of how justice can be distorted . " John Demjanjuk was later extradited to Germany on charges that he was another guard by the name of Ivan Demjanjuk , who served at the Sobibor extermination camp . During the trial , the problem of identity again became a key issue . Demjanjuk claimed he was not the Ivan Demjanjuk alleged to be a guard at Sobibor , and that the Trawnicki identification card supplied by the OSI to Germany , and on which the prosecution based its case , was a Soviet KGB forgery . On 12 May 2011 , Demjanjuk was convicted pending appeal by a German criminal court of being a guard at Sobibor extermination camp . Demjanjuk ' s appeal had not yet been heard by the German Appellate Court when he died in March 2012 . As a consequence , the German Munich District Court declared him " presumed innocent . " The court also confirmed that Demjanjuk ' s previous interim conviction was invalidated , and that Demjanuk was cleared of any criminal record . Ivan Marchenko is not on the Most Wanted Nazis list . Marchenko , if he were to be caught , would be 93 years old as of 2013 , and therefore unlikely to be brought to trial .