In addition to their work on the West Coast , Witzke and Jahnke made frequent trips east on sabotage missions . After Bopp was arrested , they gradually shifted their operations to the industrial Eastern seaboard . Double agents of the U.S. Military Intelligence Corps connected Witzke to the munitions explosion of March 1917 at the Mare Island Naval Shipyard in San Francisco . Later , Witzke himself implied that he had taken part in the massive Black Tom explosion in New York harbor on July 30 , 1916 , which killed seven people and was heard as far away as Philadelphia
Black Tom explosion
Black Tom explosion
Lothar Witzke