Perseus

Perseus was the code name of a hypothetical Soviet atomic spy that, if real, would have breached United States national security by infiltrating Los Alamos National Laboratory during the development of the Manhattan Project, and consequently, would have been instrumental for the Soviets in the development of nuclear weapons. Among researchers of the subject there is some consensus that Perseus was actually a creation of Soviet intelligence. Hypotheses include that "Perseus" was created as a composite of several different spies, disinformation to distract from specific spies, or may have been invented by the KGB to promote itself to the Soviet leadership to obtain more state funding. There were, however, multiple confirmed Soviet spies on the Manhattan project. They included Theodore Hall, George Koval, Morton Sobell, David Greenglass, Julius and Ethel Rosenberg, Klaus Fuchs, and Harry Gold.