The identity of a fourth individual involved in stealing U.S. atomic bomb secrets during and after World War II has been revealed after 70 years of secrecy.
Known to Soviets by his code name “Godsend,” Oscar Seborer was an American who worked at the Los Alamos National Laboratory in New Mexico. Before the revelation of his name, David Greenglass, Klaus Fuchs, and Theodore Hall were commonly thought to be the only three involved in a major information leak between 1940 and 1948.
Historians John Earl Haynes and Harvey Klehr discovered Seborer’s name in declassified FBI documents after persistent rumors that a fourth person could have been involved. Previous assertions that there was a fourth name were dismissed as Russian misinformation, but the historians confirmed his name in the documents detailing the covert activity.
Seborer first studied to be an engineer and then enlisted in the U.S. Army in 1942. He was assigned to work on the Manhattan Project, which designed the first nuclear weapons in the United States, including the bombs that would eventually be dropped on Japan. According to the FBI files, it was during this time that Seborer is suspected of leaking atomic secrets to the Russians. His supervisors labeled him a “security risk,” and he was eventually moved to the U.S. Navy as an electrical engineer.
Seborer, who had emigrated with his Jewish family from Poland to the United States, fled the U.S. for the Soviet Union in 1952 as relationships between the two nations deteriorated. He died in Moscow in 2015.
