Robert Hanssen

Robert Philip Hanssen (April 18, 1944 – June 5, 2023) was an American Federal Bureau of Investigation (FBI) agent who spied for Soviet and Russian intelligence services intermittently against the United States from 1979 to 2001. His espionage was described by the United States Department of Justice as "possibly the worst intelligence disaster in U.S. history".

In 1979, three years after joining the FBI, Hanssen approached the Soviet Main Intelligence Directorate (GRU) to offer his services, beginning his first espionage cycle, lasting until 1981. He restarted his espionage activities in 1985 and continued until 1991, when he ended communications during the collapse of the Soviet Union, fearing he would be exposed. Hanssen successfully reestablished communications eight years later in 1999 and continued spying until his arrest. Throughout his spying, he remained anonymous to the Russians.