John Demjanjuk was convicted of being a low-ranking guard at the Sobibor death camp, but his 35-year fight on three continents to clear his name - a legal battle that had not yet ended when he died Saturday at age 91 - made him one of the best-known faces of Nazi prosecutions. The conviction of the retired Ohio autoworker in a Munich court in May on 28,060 counts of being an accessory to murder, which was still being appealed, broke new legal ground in Germany as the first time someone was convicted solely on the basis of serving as a camp guard, with no evidence of involvement in a specific killing. It has opened the floodgates to hundreds of new investigations in Germany, though his death serves as a reminder that time is running out for prosecutors. Ukrainian-born Demjanjuk steadfastly maintained that he had been mistaken for someone else - first wounded as a Soviet soldier fighting German forces, then captured and held as a prisoner of war under brutal conditions. And he is probably best known as someone he was not: the notoriously brutal guard "Ivan the Terrible" at the Treblinka extermination camp. That was the first accusation against him, which led to him being extradited from the U.S. to Israel in the 1980s. He was tried, convicted, and sentenced to death - only to have the Israeli Supreme Court unanimously overturn the verdict and return him to the U.S. after it received evidence that another Ukrainian, not Demjanjuk, was that Nazi guard. FILE - In this May 12, 2011 file picture John Demjanjuk leaves the court room, in Munich, southern Germany. German police say John Demjanjuk, who was charged with 28,060 counts of accessory to murder and convicted last year of serving as a Nazi death camp guard, has died. Rosenheim police official Kilian Steger told The Associated Press the 91-year-old died Saturday March 17, 2012 at the home for elderly people in southern Germany where he stayed since the end of his trial in Munich last year. Demjanjuk, a retired Ohio autoworker, was deported to Germany in 2009 to face trial after being stripped of his U.S. citizenship. (AP Photo/dapd/ Lennart Preiss,File) Close "He has become at least one of the faces" of the Holocaust, Israeli historian Yehuda Bauer said in a telephone interview from Jerusalem. His case illustrates the principle that whenever even a very low-ranking Nazi criminal can be found and convicted, the importance is not in the sentence, not in the amount of time such a person may have to sit in jail ... the important thing is to bring the crime to the attention of the general public. But attorney Yoram Sheftel, who defended Demjanjuk in the Israel trial, criticized the German conviction of Demjanjuk as a Sobibor "Wachmann" - the lowest rank of the "Hilfswillige" prisoners who agreed to serve the Nazis and were subordinate to German SS men - while higher-ranking Germans were acquitted in years past. "I can only call it a prostitution of the Holocaust," he said. After his conviction in May, Demjanjuk was sentenced to five years in prison, but was appealing the case to Germany's high court. He was released pending the appeal, and died a free man in his own room in a nursing home in the southern Bavarian town of Bad Feilnbach. His son, John Demjanjuk Jr., said in a telephone interview from Ohio that his father apparently died of natural causes. Demjanjuk had terminal bone marrow disease, chronic kidney disease and other ailments and local authorities said the exact cause of death was still being determined. Demjanjuk spent most of his 18-month trial in Munich lying in a special bed brought into the courtroom, and listened to the proceedings through a Ukrainian interpreter.