William G. Sebold (Gottlieb Adolf Wilhelm Sebold ; March 10, 1899 in Mülheim, Germany – February 16, 1970 in Napa, California) was a United States citizen who was coerced into becoming a spy when he visited Germany after being pressured by several high-ranking Nazi members. He informed the American Consul General in Cologne before leaving Germany and became a double agent for the FBI. With the assistance of another German agent, Fritz Duquesne, he recruited 33 agents that became known as the Duquesne Spy Ring. In June 1941, the Federal Bureau of Investigation arrested all of the agents. They were convicted and sentenced to a total of 300 years in prison.
Early life
Sebold served in the German army engineering corps during World War I. After emigrating to the United States in 1922, he married and worked in industrial and aircraft plants throughout the United States and South America. On February 10, 1936, he became a naturalized citizen of the United States.
He returned to Germany in February 1939 to visit his mother in Mülheim. Upon his arrival in Hamburg, Germany, he was approached by a Gestapo agent who said that Sebold would be contacted in the near future due to the knowledge he obtained while working in United States aircraft factories. Sebold proceeded to Mülheim where he obtained employment.
Coerced into spying
In September 1939, a Dr. Gassner visited Sebold in Mülheim and interrogated him regarding military planes and equipment in the United States. He also asked Sebold to return to the United States as an espionage agent for Germany. Gassner and another man, a "Dr. Renken", told him that they would expose information that he had omitted from his U. S. citizenship application about serving time in a German jail unless he agreed to assist them. Renken was in fact Major Nickolaus Ritter of the Abwehr.
After the threats to his family, his life, and his citizenship, Sebold agreed to cooperate with the Nazis. He was then sent to a seven-week training program in Hamburg, Germany, where he learned to operate a clandestine shortwave radio, which he would set up when he returned to the United States.
Ritter gave Sebold final instructions before he left for the United States, including shortwave radio codes and the use of microphotographs. Sebold was given the alias "Harry Sawyer", the code name TRAMP, and Abwehr number A.3549.
Sebold was tasked to meet with various spies, pass along instructions to them from Germany, receive messages in return, and transmit them back in code to Germany. The intention was to pull off the efforts of spies who were passing technological secrets to the Germans during World War II.
Contacts U.S. embassy
Before leaving Germany, Sebold visited the U.S. Consulate in Cologne, Germany, and insisted on speaking with the Consul General. He told the Consul that he had been blackmailed into becoming a German spy but that he was a loyal American citizen and wanted to cooperate with the Federal Bureau of Investigation (FBI) in the United States. The U.S. government agreed.
Sebold sailed from Genoa, Italy, and arrived in New York City on February 8, 1940. There, Sebold (with secret help from the FBI) set himself up as a consulting diesel engineer, with an office in Times Square in Manhattan.
Duquesne Spy Ring
With the assistance of the FBI, "Harry Sawyer" was able to obtain an office in Times Square for a company under the name "Diesel Research Company". This office provided a seemingly safe space where Nazi spies felt comfortable meeting with and discussing their plans with Sebold. The office also allowed spies to send letters to manufacturers like Consolidated Aircraft Corporation, where they would then receive letters back such as "Development of Diesel Engines." The spies came to the office to deliver blueprints, wartime information, and other sensitive information regarding the United States. However, the office was outfitted with hidden microphones and two-way mirrors, so FBI agents would be able to film the meetings for future use. Using the office, the FBI were able to obtain countless hours of incriminating footage. For example, the group's leader Fritz Joubert Duquesne was caught discussing how fires could be started at industrial plants to slow production, and showed photographs of blueprints for a new bomb being built in the United States. In different footage, a spy explains his plan to bomb a building, going as far as bringing dynamite and detonation caps to Sebold's office.