Convicted Soviet spy, former FBI agent Robert Hanssen passes away in prison

Robert Philip Hanssen, who traded American secrets with the former Soviet Union for $1.4 million in cash and diamonds died in incarceration at the age of 79, according to the Federal Bureau of Prisons Monday.

Hanssen was involved in American history's most scandalous

Prison officials noted that Hanssen was unresponsive in his cell at a federal prison in Florence, Colorado, and later pronounced dead.

The former spy was reported to be died of natural causes.

The 79-year-old deceased spy revealed crucial information about US intelligence gathering including the modus operandi of US officials covering Russian spy operations, since at least 1985.

It is maintained that he was somehow responsible for the deaths of three Soviet officials who were working for US intelligence.

According to Guardian, Hanssen received over $1.4m in cash, bank funds, diamonds and Rolex watches in exchange for providing crucial information regarding national security to the Soviet Union and later Russia.

Despite monetary benefits, he was living modestly in Virginia with his family of six children and driving a Taurus and minivan.

Hanssen had said that he was motivated by money rather than ideology, but a letter written to his Soviet handlers in 1985 explains a large payoff could have caused complications because he could not spend it without setting off warning bells.

Under the alias "Ramon Garcia", Hanssen passed some 6,000 documents and 26 computer disks to his handlers, authorities said.

According to officials, they detailed eavesdropping techniques, helped to confirm the identity of Russian double agents and spilled other secrets. He tipped off Moscow to a secret tunnel the Americans built under the Soviet embassy in Washington for eavesdropping, authorities said.

He was not detected for years however in the later probe red flags were found.

"After he became the focus of a hunt for a Russian mole, Hanssen was caught taping a garbage bag full of secrets to the underside of a footbridge in a park in a dead drop for Russian handlers."

He was serving a life sentence in prison pleading guilty to 15 counts of espionage and other charges.