Three German Civilians Executed-First Pictures -- A Catholic priest kneels in prayer before Mathias Gierens, delivering the last sacrements, before the black hood is placed over his head and the executioner carries out sentence. Three German civilians, the first war criminals to be tried in Germany, were hanged at dawn on June 29, at the Military prison at Rhinebach. All three were found guilty of the murder of an American airman who parachuted to earth from his blazing bomber last August 15. T