Robert Hanssen, ex-FBI agent convicted of spying for Moscow, dies in prison

Agent who took more than $1.4m in cash and diamonds to trade secrets is believed to have died of natural causes at age 79

Robert Hanssen, a former FBI agent who took more than $1.4m in cash and diamonds to trade secrets with Moscow, in one of the most notorious spying cases in American history, died in prison Monday.

Hanssen, 79, was found unresponsive in his cell at a federal prison in Florence, Colorado, and later pronounced dead, prison officials said. He is believed to have died of natural causes, a person familiar with the matter told the Associated Press. The person was not authorized to publicly discuss details of Hanssen's death and spoke on condition of anonymity.