Jonathan Pollard's Cellmates: 8 Other Americans Who Spied on the U.S.

Former CIA officer Harold J. Nicholson was convicted in 1997 of conspiring to sell classified documented to Russia, following stints in the Army and at the U.S. Embassy in Romania. In 2010, while Nicholson was serving a 283-month sentence in a federal prison, he admitted that he had continued to act as a Russian agent for years through his son Nathaniel, who he groomed to be a spy while he was behind bars. AP

Between 1987 and 1992, Earl Edwin Pitts gave Soviet Union agents as much information as he could—from national defense documents to medical records of vulnerable agents for possible recruitment. He even admitted to giving KGB agents a key and identification badge so they could make copies and gain access to facilities in Quantico, Va. Pitts was sentenced to 27 years in prison in 1997. AP

Ronald Pelton used information he was privy to as an analyst National Security Agency to help the Soviet Union in 1980. While vacationing in Austria, Pelton walked into a Soviet Embassy and sold information on U.S. communication efforts in Russia. When he admitted to his acts of espionage in 1985, he was one of many U.S. agents caught for spying. He was sentenced to life in prison in 1986. NSA

Between 1968 and 1985, John Anthony Walker shared cryptographic messages with the Soviet Union, compromising about one million classified messages. He also recruited three additional spies including his son and brother. The FBI was finally able to uncover his activities thanks to a tip from his ex-wife in 1984. After pleading guilty, Walker was sentenced to two life terms in federal prison. Ron Edmonds—AP

As a CIA officer, Aldrich Ames was responsible for recruiting Russian officers. In an ironic twist, Ames revealed the identities of some of the Russian agents recruited by the U.S.—some were arrested and executed by the KGB. Ames was paid over $1.8 million by the Soviets during his four years as a spy. He’s currently serving a life sentence in Pennsylvania. Luke Frazza—AFP/Getty Images

Former FBI agent Robert Hanssen started spying for the Soviet Union in 1985, but wasn’t arrested until 2001. Under the code name “Ramon,” Hanssen passed along U.S. intelligence documents, including the names of American recruits whom Soviet agents later executed. He received about $600,000 for his spy efforts. In 2002, Hanssen was sentenced to life in prison without the possibility of parole. AP

David Sheldon Boone was going broke, separated from his wife, and stuck in a rut at his job as a National Security Agency analyst when started spying for the Soviet Union in 1988. After retiring in 1991 his espionage died down, but in 1998 the FBI tricked him into sharing the details of his spying. He’s currently serving what’s left of his 24-year sentence at a low security prison in Arizona. FBI

A fraud investigation into Stewart Nozette, a noted scientist who worked for several government agencies, led agents to believe he had sent top-secret government information to Israeli intelligence officers. He later handed over top-secret documents to a federal agent posing as an Israeli intelligence officer in exchange for cash. He is serving a 13-year sentence in a medium security prison in Indiana. AFP/Getty Images

Jonathan Pollard’s Cellmates: 8 Other Americans Who Spied on the U.S.

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