An 88-year-old man who appeared as a witness in the ongoing trial of suspected Nazi camp guard John Demjanjuk, faces indictment for his own alleged role as guard at the Belzec extermination camp during the Holocaust.

Samuel K., whose full name has been withheld, is suspected of being a guard at Belzec in southeastern Poland between November 1941 and spring 1943. He could face charges of accessory to murder in 430,000 cases.

“We assume that every guard in the death camp knew what was happening and participated in all activities, including sending people into the gas chambers,” Kurt Schrimm, head of Germany’s judicial authority for investigation of Nazi crimes, told Haaretz on Monday.

“We do not have testimonies of people that saw him doing this,” he said, “but we can say that he was there.”

As such, Samuel K. could be charged with the same crimes as Demjanjuk, a retired auto worker who lived for decades in the United States, now on trial in Munich for alleged crimes at the Sobibor death camp.

Samuel K. did not have a prominent position in Belzec, Schrimm said. But the German magazine Der Spiegel quoted a former comrade as saying that he had witnessed incidents in which Samuel K. had killed Jewish inmates himself, with a Belzec survivor branding him as “one of the biggest murderers.”

As a witness, Samuel K. had reportedly appeared at the trials of other suspected Nazis, but never fell under suspicion himself. During the Demjanjuk trial, however, his name came up again to police and he was questioned.

“I do not know why others did not push for charges earlier, but as soon as we learned about his testimonies we started investigating,” Schrimm said Monday.

The judicial authorities in Ludwigsburg have collected enough evidence against Samuel K. to fill an 80-page dossier, which it has handed to the department of public prosecution in Dortmund.

Schrimm told Haaretz that it is ultimately up to the Dortmund prosecutors to decide if Samuel K. will stand trial, “but we believe him to be an accessory to murder in at least 430,000 cases.”

According to Der Speigel, the alleged Nazi guard currently lives in retirement near Bonn, where he used to work as an administrative official in the federal ministry for regional planning and urban development.