Kurt Albert Jahnke ( 1882 – 1945 ) was a German-American intelligence agent and saboteur active both during World War I and World War II . Born in Gnesen , Jahnke immigrated to the United States in 1899 , became a naturalized citizen , and served in the U.S. Marines in the Philippines . From August 1914 , under the command of the German Consul General Franz Bopp , Jahnke performed various intelligence and sabotage operations for the German Admiralty from his San Francisco base . He and his assistant Lothar Witzke were responsible for the March 1917 munitions explosion at the Mare Island Naval Shipyard in San Francisco , " likely " responsible for the Black Tom explosion in Jersey City , New Jersey , and are suspected of other explosions and of fomenting labor strikes . When the United States entered the war in April 1917 , Jahnke and Witzke moved their operations to Mexico City
Black Tom explosion
Black Tom explosion
Kurt Jahnke