One month earlier than the Dasch operation (on May 14, 1942), a solitary Abwehr agent, Marius A. Langbein, was landed by a U-boat () near St. Martins, New Brunswick, Canada. His mission, codenamed Operation Grete, after the name of the agent's wife, was to observe and report shipping movements at Montreal and Halifax, Nova Scotia (the main departure port for North Atlantic convoys). Langbein, who had lived in Canada before the war, changed his mind and moved to Ottawa, where he lived off his Abwehr funds until he surrendered to the Canadian authorities in December 1944. A jury found Langbein not guilty of spying, since he had never committed any hostile acts against Canada during the war.