UPDATE — July 23, 6:30 p.m.: Johann Breyer, 89, passed away in a Philadelphia hospital on Tuesday night, his attorney told reporters.
Johann "Hans" Breyer was arrested at his home in June and and placed in Federal custody on a German arrest warrant for his work as a guard at Auschwitz during World War II.
The arrest warrant charged him with 158 counts of complicity in the commission of murder and German prosecutors were hoping to make Breyer stand trial for these charges.
Breyer had said he was a guard at Auschwitz, but that he was stationed outside of the camp.
The 89-year-old had also said he was aware of what was going on inside the death camp, but never witnessed it.
A document of Johann "Hans" Breyer's employment as a camp guard placed doubt on his claim that he never entered Auschwitz-Birkenau.
Germany's complaint alleged that Breyer served in the Death's Head Battalion.
Breyer had been under investigation by prosecutors in Germany for years in an effort to strip him of his American citizenship and be deported for trial.
Breyer's lawyer Dennis Boyle had said his client was too frail to be in custody.
Boyle argued in June during a detention hearing in federal court that Breyer was too frail to be detained.