In 1992, the American Office of Special Investigations became aware of Breyer’s role in the Waffen-SS. As a consequence, the US government immediately filed a denaturalisation action with the District Court for the Eastern District of Pennsylvania.
During the proceedings before this Court, Breyer admitted that he served as a “Death’s Head” guard at Buchenwald and was later transferred to Auschwitz. However, he stated that he was only patrolling the perimeter of the camps, and that only on three or four occasions did he march prisoners to construction sites outside the camp complex.
In 2003, the US Court of Appeals for the Third Circuit ruled that he was not responsible for joining a Nazi unit because he was only 17 years old at the time, and was coerced into doing so.
A separate investigation was subsequently opened by the German District Court of Weiden. The prosecution, which found new evidence of Breyer’s alleged active participation in the mass killings in Auschwitz concentration camp, charged him on 17 June 2013 with 158 counts of aiding and abetting the murder of more than 216’000 European Jews from Hungary, Germany, and Czechoslovakia, who were forcibly deported to the camp on 158 trains between May and October 1944.
The investigation showed that Breyer had been promoted at least once while stationed at Auschwitz, and had been granted leave to visit his family twice. The prosecution asserted that only guards willing to perform the full range of duties arising from the belonging to the “Death’s Head” Battalion benefited from such treatment. As part of their routine, the “Death’s Head” guards were not only responsible for preventing escapes along the perimeter of the camp, but were also in charge of the selection of the deported population to the gas chambers.
Along with the indictment, the District Court of Weiden issued an arrest warrant for Breyer
On the basis of an extradition treaty existing between the US and Germany, Breyer was arrested by the American authorities in Philadelphia, Pennsylvania on 17 June 2014. He was immediately placed in federal custody, pending an extradition hearing scheduled for 21 August of the same year. As the crimes he was accused of were extremely serious, he was denied baill.
However, because of health problems, Breyer was transferred in July to Jefferson University Hospital in Philadelphia. His health rapidly deteriorated, and he finally died on 22 July 2014, prior to his hearing.