Klaus Fuchs arrested for passing atomic bomb information to Soviets - Feb 03, 1950 - HISTORY.com

Klaus Fuchs, a German-born British scientist who helped developed the atomic bomb, is arrested in Great Britain for passing top-secret information about the bomb to the Soviet Union. The arrest of Fuchs led authorities to several other individuals involved in a spy ring, culminating with the arrest of Julius and Ethel Rosenberg and their subsequent execution.

Fuchs and his family fled Germany in 1933 to avoid Nazi persecution and came to Great Britain, where Fuchs earned his doctorate in physics. During World War II, British authorities were aware of the leftist leanings of both Fuchs and his father. However, Fuchs was eventually invited to participate in the British program to develop an atomic bomb (the project named “Tube Alloys”) because of his expertise. At some point after the project began, Soviet agents contacted Fuchs and he began to pass information about British progress to them. Late in 1943, Fuchs was among a group of British scientists brought to America to work on the Manhattan Project, the U.S. program to develop an atomic bomb. Fuchs continued his clandestine meetings with Soviet agents. When the war ended, Fuchs returned to Great Britain and continued his work on the British atomic bomb project.

Fuchs’ arrest in 1950 came after a routine security check of Fuchs’ father, who had moved to communist East Germany in 1949. While the check was underway, British authorities received information from the American Federal Bureau of Investigation that decoded Soviet messages in their possession indicated Fuchs was a Russian spy. On February 3, officers from Scotland Yard arrested Fuchs and charged him with violating the Official Secrets Act. Fuchs eventually admitted his role and was sentenced to 14 years in prison. His sentence was later reduced, and he was released in 1959 and spent his remaining years living with his father in East Germany.

Fuchs’ capture set off a chain of arrests. Harry Gold, whom Fuchs implicated as the middleman between himself and Soviet agents, was arrested in the United States. Gold thereupon informed on David Greenglass, one of Fuchs’ co-workers on the Manhattan Project. After his apprehension, Greenglass implicated his sister-in-law and her husband, Ethel and Julius Rosenberg. They were arrested in New York in July 1950, found guilty of conspiracy to commit espionage, and executed at Sing Sing Prison in June 1953.