John Demjanjuk, the 89-year old former autoworker accused of war crimes who lived for decades in a Cleveland suburb, went on trial in Germany on Monday on charges of helping to kill 27,900 Jews at a Nazi Treblinka death camp in Poland.

The trial represents the culmination of 30 years of work by Nazi hunters and prosecutors have Demjanjuk face justice. As the Associated Press reports, Demjanjuk was once extradited to Israel where he was tried, convicted and imprisoned, only to have his conviction eventually overturned.

He was convicted in 1988 of war crimes and crimes against humanity, and spent seven years in prison until Israel's Supreme Court overturned the conviction in 1993. It ruled that another person, not Demjanjuk, was actually "Ivan the Terrible."

Demjanjuk, a former Soviet Red Army soldier, is now accused of volunteering to serve as a guard under the SS after being taken prisoner by the Nazis in 1942.

According to the indictment, he served as a simple "wachmann," or guard, under the SS. As such, he is the lowest-ranking person to go on trial for Nazi war crimes.

The prosecution argues that, even with no living witnesses who can implicate Demjanjuk in specific acts of brutality or murder, just being a guard at a death camp means he was involved in the Nazis' machinery of destruction.