Attorneys for John Demjanjuk want an American court in Cleveland to set aside the ruling that led to his deportation to Germany and his conviction on Nazi war crimes charges.

The request for a new hearing on the retired autoworker's denaturalization could bring the decades-old case back to the United States.

Demjanjuk's attorneys charge that the government failed to disclose important evidence, namely a 1985 secret FBI report uncovered by The Associated Press that indicates the FBI believed a Nazi ID card purportedly showing Demjanjuk served as a death camp guard was a Soviet-made fake.

"The government has kept these materials hidden from view," according to the motion filed Tuesday in U.S. District Court in Cleveland.

Demjanjuk, 91, was convicted in a German court on May 12 of 28,060 counts of accessory to murder, finding that he served as a guard at the Nazi's Sobibor death camp in occupied Poland. He was sentenced to five years in prison.

Ukrainian-born Demjanjuk was a Soviet Red Army soldier captured by the Germans in 1942. The Munich court found he agreed to serve the Nazis as a guard at Sobibor.

Demjanjuk denies serving as a guard at any camp and is currently free pending his appeal. He's been in poor health for years and has been in and out of a hospital since his conviction.

He currently cannot leave Germany because he has no passport, but he could get a U.S. passport if the denaturalization ruling is overturned.