The man, retired toolmaker Johann "Hans" Breyer, was arrested by U.S. authorities Tuesday night. Breyer spent the night in custody and appeared frail during a detention hearing in federal court, wearing an olive green prison jumpsuit and carrying a cane.
Legal filings unsealed Wednesday in the U.S. indicate the district court in Weiden, Germany, issued a warrant for Breyer's arrest the day before, charging him with 158 counts of complicity in the commission of murder.
Each count represents a trainload of Nazi prisoners from Hungary, Germany and Czechoslovakia who were killed at Auschwitz-Birkenau between May 1944 and October 1944, the documents said.
Attorney Dennis Boyle argued his client is too infirm to be detained pending a hearing on his possible extradition to Germany. Breyer has mild dementia and heart issues and has previously suffered strokes, Boyle said.
"Mr. Breyer is not a threat to anyone," said Boyle. "He's not a flight risk."
But Magistrate Judge Timothy Rice ruled the detention center was equipped to care for Breyer, who appeared to comprehend questions about the nature of the hearing.
A law enforcement officer also testified Breyer and his elderly wife grasped what was happening during his arrest Tuesday outside their home in northeast Philadelphia.
"They both understood," deputy marshal Daniel Donnelly said. "It wasn't news to them."
Breyer has been under investigation by prosecutors in the Bavarian town of Weiden, near where he last lived in Germany.
Breyer has admitted he was a guard at Auschwitz in occupied Poland during World War II, but has told The Associated Press he was stationed outside of the Auschwitz-Birkenau death camp part of the complex and had nothing to do with the wholesale slaughter of about 1.5 million Jews and others behind the gates.
Thomas Walther, a former federal prosecutor with the special office that investigates Nazi war crimes in Germany, now represents family members of some of Breyer's alleged victims as co-plaintiffs in the case. He called for a speedy extradition.
"The German court has to find late justice for the crimes of Breyer and for the victims and their sons and daughters as co-plaintiffs," Walther wrote in an email to the AP. "It is late, but not too late."
Prosecutors in Weiden could not be reached for comment Wednesday. Their investigation comes after years of failed U.S. efforts to have Breyer stripped of his American citizenship and deported.
A court ruling in 2003 allowed him to stay in the United States, mainly on the grounds that he had joined the SS as a minor and could therefore not be held legally responsible for participation in it. His American citizenship stems from the fact his mother was born in the U.S.; she later moved to Europe, where Breyer was born.
During Breyer's arrest Tuesday, he asked the marshals to retrieve papers in his home that document his right to stay in the U.S., Donnelly testified.
Breyer's wife and two grandsons attended the hour-long hearing in Philadelphia on Wednesday. His extradition hearing was scheduled for Aug. 21.
Efraim Zuroff, the head Nazi hunter at the Simon Wiesenthal Center in Jerusalem, said he hoped there would be no obstacles to Breyer's extradition and trial overseas.
"Germany deserves credit for doing this - for extending and expanding their efforts and, in a sense, making a final attempt to maximize the prosecution of Holocaust perpetrators," he said in a telephone interview from Jerusalem.
Associated Press writer David Rising in Berlin contributed to this report.