The hunt for a monster can warp the pursuers. The wanted man was one of the most loathsome creatures of modern times: “Ivan the Terrible,” who hacked at his naked victims with a sword as he herded them by the thousands into the gas chambers he operated at the Nazi death camp Treblinka. American and Israeli officials were certain they had found him in John, formerly Ivan, Demjanjuk, a retired suburban Cleveland autoworker of Ukrainian descent. He was extradited to Israel in 1986, where he was convicted of crimes against humanity and condemned to hang after a dramatic trial that transfixed the nation. , This week Israel’s highest court will finally render its judgment on Demjanjuk’s appeal, for which hearings were completed just over a year ago. Yoram Sheftel, Demjanjuk’s lawyer, feels “fully confident” his client will go free; Israelis, in fact, are steeling themselves for the prospect that what may be the last major Nazi war trial will end in failure. New evidence supporting Demjanjuk’s contention that he was the victim of mistaken identity has convinced many observers that while he may be Ivan the Not Very Nice, accountable for lesser crimes, Demjanjuk will be cleared of the atrocities of Treblinka’s notorious Ivan. Doubts about the case intensified last month when a U.S. federal judge, appointed to investigate where Justice Department officials had mishandled their prosecution of Demjanjuk concluded that there was “substantial doubt” he was Ivan the Terrible. Judge Thomas A. Wiseman Jr. criticized government lawyers for being insufficiently inquisitive about the facts of the case but said their failings fell short of misconduct. In his report to the U.S. Sixth Circuit Court of Appeals, Wiseman recommended that the extradition be upheld because even if Demjanjuk was not at Treblinka, evidence indicated he was an agent of the SS nonetheless. In a case so important, how could the authorities, both American and Israeli, have got it so wrong? At the time of Demjanjuk’s denaturalization, extradition and conviction, they did not have the full body of evidence available today: statements made to Soviet authorities by 32 former guards and five forced laborers at Treblinka, all hailing from what was then the Soviet Union. They said a man named Ivan Marchenko was the Ivan of Treblinka. Marchenko, like Demjanjuk a native Ukrainian, was last seen in Yugoslavia in 1944. The statements of these 37, most of whom were executed by the Soviets as Nazi collaborators, were not obtained by Israeli courts until 1991. But as early as 1978, U.S. officials who handled Demjanjuk’s case had the testimony of two of the guards, a fact they withheld from Demjanjuk’s lawyers. The evidence did seem to indicate that Demjanjuk had been a Nazi collaborator: an identity card supplied to the Americans by the Soviets, who claimed to have discovered it among German documents seized in the war, indicated he had been trained as a Wachmann, or guard, for the SS. U.S. officials thought Demjanjuk and Marchenko were one and the same. In his 1951 application for a U.S. visa, Demjanjuk incorrectly listed his mother’s maiden name as Marchenko. He said he had forgotten her real name and simply selected a common Ukrainian surname, but his choice gave rise to speculation that he had used Marchenko as an alias at Treblinka.