The prosecution relied heavily on the testimony of Holocaust survivors to establish that Demjanjuk had been at Treblinka, five of whom were put on the stand. Four of the survivors who had originally identified Demjanjuk's photograph had died before the trial began. The testimony of one of these witnesses, Pinhas Epstein, had been barred as unreliable in US denaturalization trial of former camp guard Feodor Fedorenko, while another, Gustav Boraks, sometimes appeared confused on the stand. The most important of these was Eliyahu Rosenberg. Asked by the prosecution if he recognized Demjanjuk, Rosenberg asked that the defendant 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 learned that Eliyahu Rosenberg had previously testified in a 1947 deposition that "Ivan the Terrible" had been killed in 1943 during a Treblinka prisoner uprising. During the trial, Demjanjuk was again identified on the photo spread by Otto Horn, a former German SS guard at Treblinka.