If an American judge approves their request, Breyer, who has lived in a redbrick rowhouse near Pennypack Park for nearly four decades, would become the oldest person extradited from the United States to face allegations of Nazi-related crimes.
His lawyer, Dennis Boyle, vowed a fight. In recent years, Breyer has suffered a series of ministrokes, and is being treated for a heart condition and dementia.
"I think it is obvious Mr. Breyer is not a risk to anyone," he said in court Wednesday. "He's very old."
Breyer has never denied that he was stationed at Auschwitz, in Nazi-occupied Poland, but he maintained his duties consisted solely of guarding the perimeter of the death camp.
He told the Associated Press in a rare 2012 interview that he had nothing to do with the gas chambers that killed hundreds of thousands during the war. He has lived a lawful life since immigrating to the United States in 1952, he added.
"I didn't kill anybody, I didn't rape anybody, and I don't even have a traffic ticket here," he said.
The octogenarian who sat before U.S. Magistrate Judge Timothy Rice during a brief court appearance cut a far different figure from the strapping youth described in court filings unsealed Wednesday as standing watch outside the camp's gates as thousands were gassed inside.
Asked by the judge whether he understood what was happening, Breyer initially replied, "Not really."
Later, though, he was able to identify his lawyer and the court, and acknowledged that he understood that German authorities were seeking to prosecute him.
Still, even as Rice announced his decision to hold Breyer in custody until a full extradition hearing next month, Breyer interrupted, asking his lawyer who the woman was sitting at the opposite table.
"That's the U.S. attorney," Boyle whispered back.
Breyer's arrest Tuesday revived a legal fight he thought he had put behind him years ago. The Justice Department first challenged his Nazi ties in 1992, alleging that he had lied about his war record when he came to this country.
In 2003, a federal court chose to let him stay here, finding that he had joined the SS as a minor and could not be held legally responsible. He derives U.S. citizenship from his mother, who was born in Manayunk.
But for German authorities, that is no longer enough. Since the 2011 conviction in Munich of John Demjanjuk, an Ohio man who served at the notorious Sobibor death camp in Poland, prosecutors there have successfully pursued others under the legal theory that soldiers who worked in support roles at the camps are as culpable as those who directly killed.
"He is charged with aiding and abetting those deaths," Assistant U.S. Attorney Andrea Foulkes said Wednesday. "Proof doesn't require him to have personally pulled any levers. His guarding made it possible for those killings to happen."
Breyer's lawyers have portrayed the Breyer of 1942 as a scared 17-year-old taken from his family farm in what was then Slovakia and pressed into Nazi service. U.S. court filings unsealed Wednesday painted a different picture.
Breyer voluntarily enlisted, responding to a call to ethnic German youths, the documents state. He was called up a year later and deployed with the Waffen-SS Death's Head Guard Battalions to Auschwitz-Birkenau through 1944.
That year, more than 437,000 Hungarian Jews arrived at the camp, nearly half of them being exterminated upon arrival.
Though Breyer earlier maintained he was given leave to return to his family's farm in August 1944 and never returned to the camp, the complaint outlines a series of historical records that suggest he remained at Auschwitz until 1945.
And as authorities arrived at his home Tuesday to take him into custody, Breyer seemed to know exactly how serious his situation had become, Deputy U.S. Marshal Daniel Donnelly said in court Wednesday.
The deputies met him and his wife, Shirley, in their driveway as the pair returned from a doctor's appointment and a trip to buy a new air conditioner. Breyer asked his wife to retrieve some legal documents before he was taken away.
His wife asked the marshals to help her carry the air conditioner inside.
"They both understood," Donnelly said. "It wasn't news to them."
Inquirer staff writer Casey Fabris contributed to this article.