Ritter employed several other successful agents across the US, most notably Herman Lang, who delivered to the Germans the blueprints for the Norden bombsight, but he also made the mistake of recruiting a man who would later become a double agent, William Sebold. On 8 February 1940, Ritter sent Sebold to New York under the alias of Harry Sawyer and instructed him to set up a shortwave radio-transmitting station to establish contact with the German shortwave station abroad. Sebold was also instructed to use the code name TRAMP and to contact a fellow agent code named DUNN, who was Duquesne.
Ritter utilized several other effective agents throughout the US, particularly Herman Lang, who provided German forces with blueprints for the Norden bombsight. However, he also made a mistake by recruiting William Sebold, who later became a double agent. On February 8, 1940, Ritter sent Sebold to New York under the alias of Harry Sawyer and instructed him to set up a shortwave radio-transmitting station for communication with a German shortwave station abroad. Sebold was also directed to use the code name TRAMP and contact another agent named Dunn.