Former FBI agent who spied for Russia found dead in prison cell

A former FBI agent who was convicted of spying for the Soviet Union and later the Russian Federation was found dead in his prison cell on Monday morning.

Robert Hanssen pleaded guilty after his 2001 arrest to selling classified materials the USSR and its successor state. The Bureau of Prisons confirmed his death at the age of 79, according to CBS News. He was serving a life sentence.

Prison officials indicated that he was found unresponsive but that medical personnel pronounced him dead despite life-saving efforts.

Hanssen's stint as a Muscovite agent spanned four decades. He first began spying for the Soviets in 1979 and continued passing information to Moscow after the Union's collapse.

Apart from selling classified materials, he exposed American spies and double agents, leading to their executions. He was not caught until 2001, when he was arrested after making a dead drop in a Virginia park.

Ben Whedon is an editor and reporter for Just the News. Follow him on Twitter.