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Foreign Counterintelligence



Operation SOLO was a long-running FBI program to infiltrate the Communist Party of the United States and gather intelligence about its relationship to the Union of Soviet Socialist Republics, China, and other communist nations. It officially began in 1958 and ended in 1977, although Morris and Jack Childs, two of the principal agents in the operation, had been involved with the Bureau for several years prior. The files range from March 1958 to April 1966. Read a related story at

Bernard Julius Otto Kuehn

Bernard Julius Otto Kuehn (1895-Unknown) and his wife were German-born spies for the Japanese government. They provided the Japanese with intelligence related to the attack on Pearl Harbor, Hawaii on December 7, 1941. After serving a long prison sentence, Kuehn and his family were deported to Germany. For more information, see:

William Remington

William Walter Remington (1917-1954) was a government economist accused by Elizabeth Bentley of cooperating in espionage for the Soviet Union during World War II. He was convicted of perjury in 1953 for denying that he had provided Bentley with technical data related to war production and earlier ties to a communist group. Remington was murdered in jail in 1954. This release contains materials relating to the investigation of the espionage matters and his security clearance investigations. The files cover from 1941 to 1954.

Klaus Fuchs

Klaus Emil Julius Fuchs (1911-1988) was a German-born atomic scientist who emigrated to Great Britain in the late 1930s. He worked on the joint U.S./British effort to build the atomic bomb. Following an FBI and British investigation, Fuchs was convicted of espionage in Great Britain for supplying atomic secrets to the Soviet Union. The Fuchs file is tied closely to that of Julius and Ethel Rosenberg, two U.S. citizens who were convicted in 1950 of passing atomic secrets to the USSR. The file ranges from 1949 to 1976.

Morton Sobell

Morton Sobell (1917-) was an electrical engineer who was found guilty in 1951 of spying for the Soviet Union. These files range from 1942 to 1977. The bulk of the material consists of the investigation into Sobell’s connections to the Rosenberg spy ring.
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