Abstract
Years before anything was publicly disclosed about the nuclear espionage of Julius and Ethel Rosenberg, Klaus Fuchs, and Theodore Hall, the U.S. Federal Bureau of Investigation (FBI) and U.S. Army Intelligence identified Clarence Hiskey, a Manhattan Project scientist, as a Soviet spy helping to provide highly sensitive nuclear weapons information. The two agencies kept watch on a Soviet intelligence officer, Arthur Adams, who was living illegally in the United States and serving as Hiskey's control officer. Despite an extensive investigation, neither Hiskey nor Adams was ever arrested. Although Adams was named in a sensational tabloid newspaper article shortly after the end of World War II and closely shadowed by the FBI, he was able to flee to the Soviet Union. Hiskey was never indicted for espionage. Based on material released from declassified Russian archives and FBI files made available under the Freedom of Information Act, the article tells the story of the first U.S.-based nuclear spy and how he got away with it.