Robert Hanssen's arrest marked one of the most significant espionage cases in U.S. history. An FBI agent since 1976, Hanssen's betrayal extended over two decades, during which he provided a wealth of classified information to Soviet intelligence and later to the Russians. His motivations included financial gain, personal vanity, and a deep-seated belief in his own intelligence superiority. The information he disclosed included sensitive data on U.S. intelligence operations and the identities of American spies in Soviet and Russian territories.

Hanssen was arrested in a sting operation led by the FBI in February 2001. He had been under investigation for several years and was caught red-handed while attempting to pass information to what he believed was a Russian agent, but was actually an undercover FBI agent. Following his arrest, a massive review unfolded into the extent of his data breaches, leading to the identification and possible range of damage incurred by the compromising of U.S. intelligence efforts.

After being charged, Hanssen pled guilty to 15 counts of espionage and conspiracy, admitting to passing sensitive information in exchange for over $1.4 million in cash and other benefits. His betrayal not only represented a personal failure for the FBI but also resulted in a significant erosion of trust, prompting policy changes within the agency and leading to greater scrutiny of insider threats. The case raised questions about how to effectively safeguard intelligence operations and the importance of monitoring personnel for potential security risks.