West German jurist, plotter against Hitler and defector to the German Democratic Republic. John was involved in the plot of 20 July 1944 to assassinate Adolf Hitler, for which his brother, Hans, was executed. At the time, he worked as a lawyer at the Deutsche Lufthansa legal office in Madrid and used contacts he had made with British intelligence to escape to England. After the war he was appointed as the first head of West Germany's domestic intelligence service, the Office for the Protection of the Constitution, from 1950 to 1954. He is best known for his controversial move to East Germany in 1954, which has been interpreted as treason or an abduction. In 1955 he defected back to West Germany, claiming he was kidnapped by the KGB.