John Demjanjuk, who was discovered 30 years ago working as an auto mechanic in Ohio and spent the rest of his life facing charges of being a Nazi death camp guard, has died at age 91 of natural causes, his son John Demjanjuk Jr. said.

The Ukrainian-born Demnjanjuk was extradited to Israel in 1986 to face charges that he was Ivan the Terrible, a notoriously brutal guard at the Treblinka extermination camp. He was found guilty and sentenced to death, but the ruling was overturned by the Israeli Supreme Court in 1993 when another Ukrainian was identified as that guard.

He returned to Cleveland and had his U.S. citizenship reinstated, but later evidence arose that Demjanjuk had served as a guard at the Trawniki SS training camp and Sobibor. In 2005, it was ruled that he could face extradition, and he was sent to Germany in 2009 to face war crimes charges. A photo ID convinced a panel of judges in Munich that he was guilty of acting as "an accessory to the murder of 27,900 Jews" -- the number killed during his period there -- and Demjanjuk was sentenced to five years in prison. He was released pending an appeal, and lived out his last days at a nursing home in Bad Feilnbach, Germany. He denied the charges until the end.