Robert Philip Hanssen (April 18th, 1944 - ) is a former senior FBI agent assigned to counterintelligence who was a spy for the Soviet Union and later post-Soviet Russia. He pleaded guilty in 2002 to espionage for passing classified information to the Soviet Union and later to Russia over a 20-year period, which was regarded as the worst intelligence disaster in U.S. history at the time. His actions were extremely treacherous and even lead to the deaths of several KGB agents working with the FBI.
