CIA mourns 'most valuable' KGB defector

A KGB spy who switched allegiances at the height of the Cold War and was considered by the CIA as its “most valuable and economical defector” has died.

Yuri Ivanovich Nosenko defected in Switzerland in 1964.

Confined to a safe house in Clinton, Maryland, outside Washington, the former Soviet spy was interrogated for about four months in 1965 until transferred to a specially constructed jail because he was suspected of being a double agent, according to decades-old CIA documents released last year.

He was held until October 1967, then resettled under an assumed identity.

“While I regret my three years of incarceration, I have no bitterness and now understand how it could happen,” he said, according to the documents.

The 81-year-old Mr Nosenko died on Saturday, a month after the CIA delivered to his home a ceremonial flag and a letter of thanks from the agency’s director, Michael Hayden, honouring his service to the United States, according to intelligence officials.

The CIA considered Mr Nosenko the “most valuable and economical defector this agency has ever had”, the long-held documents said, noting his information resulted in the arrest and prosecution of spies.

The US spy agency also gave Mr Nosenko polygraph tests in 1964, 1966 and 1968 about possible ties between the KGB and Lee Harvey Oswald, the man who assassinated President John F. Kennedy.

Mr Nosenko told his interrogators that Oswald was not a KGB operative, according to a 1979 report to Congress.