A 91-year-old retired autoworker was convicted on Thursday of helping the Nazis murder at least 28,000 Jews at the Sobibor death camp during World War II. A Munich court has sentenced John Demjanjuk to five years in prison following 18 months of trial. Demjanjuk is believed to have been a Russian prisoner of war in 1942, who was trained as a guard at a camp in Trawniki. He was transferred to Sobibor in 1943, at which point he became known as one of the so-called ‘Trawniki men’, whose job it was to help systematically kill Jews. “Every Trawniki man knew that he was part of a well and smoothly operating apparatus that had no other goal than systematically murdering Jews,” said Ralph Alt, the presiding judge. “They all knew about the barbaric treatment of Jews. And the accused was part of that extermination machinery.” This ruling may be one of Germany’s last major Holocaust trials, Bloomberg reports.