The New York Times reports officials have reopened a case against Johann Breyer, an 89-year-old Czechoslovakia immigrant tool maker living in Philadelphia, who has been accused of working as a Nazi guard at the Auschwitz and Buchenwald concentration camps. Breyer was arrested at his home in Philadelphia on Tuesday, and appeared in Federal District Court on Wednesday to face charges.

Breyer was first arrested and nearly deported by the Justice Department in 1992, but he eventually won a long legal fight was allowed to stay. Germany reopened their case against Breyer in 2012, and, as recently as May 2013, asked the U.S. for help investigating Breyer. "Germany is seeking to have him extradited to stand trial under a sealed German indictment made public on Wednesday," the Times reports. 

Breyer has admitted to serving as a Nazi guard at Auschwitz I, a slave camp that mostly used for forced labor, but denies that he was ever posted to Auschwitz II, where some of the Nazis' most heinous crimes took place. The new charges brought against Breyer are at least in part based on Nazi administrative documents the Justice Department released to the AP in 2012 that showed Breyer's name among a list of guards at Auschwitz II. Per the Times

Officials say newly discovered evidence has strengthened their case against Mr. Breyer. War-era records indicate that he was at Auschwitz earlier in the war than he acknowledged and that he served as a guard in a particularly notorious subcamp, known as Birkenau or “Auschwitz 2,” which was used exclusively to kill prisoners.