Canada’s last mass execution saw five men hanged in the early morning hours of Dec. 18, 1946, in the provincial jail in Lethbridge, Alta. One was a Canadian Army veteran, who had sexually assaulted and murdered two young boys, and — having been convicted in Calgary — was sent to Lethbridge to join the other four. The hangman, known by his pseudonym Camille Branchaud, was really there for them. They were German prisoners of war convicted of killing a fellow Second World War PoW, Karl Lehmann, in Alberta’s Medicine Hat PoW Camp 132 in July 1944. Their executions, and that...