Rudolf Abel

One of many aliases for William Fischer, an undercover Soviet agent who entered the United States in 1948 on a forged passport. He posed as an eccentric artist while leading a KGB spy ring in New York . His network kept in contact with Soviet agents trying to steal U.S. atomic secrets, including Julius and Ethel Rosenberg.

Eventually he was betrayed by a former member of his network, and in 1960 he was sentenced to 30 years in prison. A few years later, however, he was released to the Soviets in exchange for downed U-2 pilot Francis Gary Powers.