A US military historian told the war crimes trial of John Demjanjuk that he doubted the retired Ohio car worker’s account of his whereabouts in the last years of the Second World War.

The trial in Germany of an alleged Nazi death camp guard was postponed today after reports the 89-year-old defendant was experiencing health problems.

A judge today revoked the US citizenship of John Demjanjuk, agreeing with government allegations that he was a Nazi concentration camp guard.