One of the most notorious spies and traitors in American history is dead.
Former FBI agent Robert Hanssen was found dead in his prison cell on Monday morning, according to The New York Times.
Hanssen was serving 15 consecutive life sentences.
The federal agent plead guilty to providing national security information to the Soviet Union and Russia in 2002 — serving as a source for foreign intelligence operatives over the course of decades.
Hanssen was incarcerated in Colorado at a “supermax” federal prison used to detain prisoners of special concern to national security.
Bureau of Prisons Director of Communications Kristie Breshears indicated that the 79-year-old Hanssen was unresponsive to life-saving measures in a statement provided to CBS News.
“Staff requested emergency medical services and life-saving efforts continued.”
BREAKING INTEL: @CBSNews has confirmed that Robert Hanssen, a former @FBI agent and one of the most damaging spies in U.S. history, has died. He was found unresponsive this morning, per the Bureau of Prisons. Hanssen was 79 and had spent the last 22+ years in federal custody. pic.twitter.com/ZBHKvdojAA
— The Spy Museum (@IntlSpyMuseum) June 5, 2023
“The inmate was subsequently pronounced dead by outside emergency medical personnel.”
Hanssen received more than $1.4 million in compensation from Soviet and Russian officials in exchange for classified documents of grave importance to U.S. national security, according to CBS.
Information that Hanssen provided to Russian intelligence cost some KGB personnel operating as double agents for the U.S. government their lives, according to the Guardian.
FBI Director Louis Freeh described Hanssen’s actions as one of the worst national security breaches in American history.
“The FBI entrusted him with some of its most sensitive matters and the US government relied upon him for his service and integrity,” Freeh said of Hanssen in 2001.
Hannsen’s guilty plea allowed him to avoid the death penalty.
Some materials he exchanged outlined American strategy in the event of a nuclear war.
The spy was ultimately apprehended after a Russian intelligence officer provided materials with Hanssen’s fingerprints and a recording of his voice to the FBI.
Hanssen’s cause of death is unclear, according to the Times.
This article appeared originally on The Western Journal.