 At the beginning of the Second World War, Gehre was active as a captain in the Abwehr (military intelligence) under Admiral Wilhelm Canaris.By 1939, a group in the Abwehr had formed to remove the Nazi regime and end the war.This circle included Canaris, General Ludwig Beck, Hans von Dohnanyi, Hans Oster and Dietrich Bonhoeffer, as well as Gehre.