Mr Demjanjuk says he was a prisoner of war with the Nazis
German investigators have said they have enough evidence for charges to be brought against an alleged Nazi death camp guard who now lives in the US.
They said they had obtained new files that would prove John Demjanjuk, 88, was responsible for the death of 29,000 Jews at a camp in Nazi-occupied Poland.
They said they would now ask German prosecutors to request his extradition.
Mr Demjanjuk was sentenced to death in Israel in the 1980s, but was then acquitted and returned to the US.
Born Ivan Demjanjuk in Ukraine, he had migrated to the US in the 1950s. He denies any involvement in Nazi crimes.
The file on Mr Demjanjuk was compiled by the special German office investigating Nazi crimes.
Kurt Schrimm, who heads the office, told Reuters that investigators "have managed to obtain hundred of documents and have also found a number of witnesses who spoke out against Demjanjuk".
"For the first time we have even found lists of names of the people who Demjanjuk personally led into the gas chambers. We have no doubt that he is responsible for the death of over 29,000 Jews" at the Nazis' Sobibor death camp, he said.
Mr Schrimm added that the investigators' report had already been submitted to prosecutors in Munich - where Mr Demjanjuk lived briefly after the war - to press for his extradition.
Mr Demjanjuk has always insisted he was a prisoner of war of the Nazis, rather than a guard serving under them.
Mr Demjanjuk emigrated to the US in 1952.
In 1986, he was extradited to Israel and sentenced to death for war crimes, after being identified by witnesses as "Ivan the Terrible", a notorious prison guard at the Treblinka camp.
But the Israeli Supreme Court overturned his conviction, when new evidence emerged suggesting he was not the same guard.
He returned to the US but was accused of lying on his immigration application about working for the Nazis.
In 2002, a US immigration judge ruled that there was enough evidence to prove Mr Demjanjuk had been a guard at several Nazi death camps and stripped him of his citizenship.
Earlier this year, the retired Ohio car worker lost his legal fight to stay in the US.