The Man Who Finally Died(1963)

...The mystery of the century explodes!.. An espionage hunt across sinister post-war Europe!

Joe Newman, a naturalised Briton, is telephoned by his German father, whom he believed long dead, at the same time as a funeral is taking place in Bavaria - with his father's name on the coffin. His investigation in Bavaria reveals startling facts and the obstruction he meets makes him suspect foul play.