Former Nazi death camp guard John Demjanjuk, convicted in Germany last year of helping kill some 28,000 prisoners, died Saturday at the age of 91.

Police in the southern German state of Bavaria say the ailing Demjanjuk died in a nursing home in the town of Bad Feilnbach. He had been sentenced last May to five years in prison, but was freed pending an appeal.

The Ukrainian-born Demjanjuk denied any role in the Holocaust and claimed that he was a victim of the Nazis himself. He told the court he was drafted into the Soviet army in 1941, held as a German prisoner of war and recruited as a prison camp guard.

After the World War II, Demjanjuk became a U.S. citizen and spent decades working as a mechanic before he was extradited to face trial in Germany in 2009. His conviction set a legal precedent in Germany, marking the first time someone was convicted solely on the grounds of serving as a camp guard, with no evidence of being involved in a specific crime.

In 1988, Demjanjuk was convicted in Israel of being the notorious guard known as “Ivan the Terrible.” Israel's Supreme Court later overturned the conviction as a case of mistaken identity.