FREMONT COUNTY, Colo. — A former FBI agent who was imprisoned at the "Supermax" prison in Florence after spying for the Soviet Union and Russia between 1979 and 2001 died on Monday.
Robert Hanssen, 79, was found unresponsive just before 7 a.m. Monday at ADX Florence, which is part of the Federal Correctional Complex in Florence, according to a statement from the U.S. Bureau of Prisons. ADX stands for "administrative maximum."
Staff began life-saving measures and requested emergency medical services, but Hanssen was pronounced deceased.
No other staff or inmates were injured and the Federal Bureau of Investigation was notified.
He took more than $1.4 million in cash and diamonds to trade secrets with Russia and the former Soviet Union during and after the Cold War in one of the most notorious spying cases in American history, according to The Associated Press. The AP learned from a person familiar with the matter that he likely died of natural causes.
He had been serving a sentence of life in prison without parole after pleading guilty to 15 counts of espionage and other charges in 2001, according to the AP.
Hanssen has been in custody at ADX Florence, a maximum-security facility, since July 17, 2002. It currently houses 315 male offenders.
The federal prison houses inmates that are deemed to be the most dangerous. It is so secure that it has been nicknamed the “Alcatraz of the Rockies.”
Unabomber Ted Kaczynski, Boston Marathon bomber Dzhokhar Tsarnaev, Sept. 11 conspirator Zacarias Moussaoui, billionaire drug lord El Chapo, and Oklahoma City bombing accomplice Terry Nichols are among those who call it home, according to the AP.
