The identification and business card of former FBI agent Robert Hanssen are seen inside a display case at the FBI Academy in Quantico, Virginia, on May 12, 2009.
The FBI called him "the most damaging spy in bureau history."
Hanssen joined the FBI in 1976 after first serving as a policeman in Chicago.
Robert Hanssen, the notorious FBI double agent who secretly fed Russia some of America's deepest secrets in the 1980s and 1990s, died in a top-security prison Monday, prison officials said.
Offering himself to Soviet military intelligence in 1985, Hanssen traded government secrets and the identities of US moles in the Soviet and Russian governments in exchange for diamonds and hundreds of thousands of dollars.
