A GHOST from the cold war has returned to haunt the CIA. A book to be published this month by a veteran American spy is raising startling new questions about Yuri Nosenko, the Russian defector who played a key part in the inquiry into the assassination of President John F Kennedy. Conspiracy theorists have long been obsessed with Nosenko’s supposed role as the KGB officer who handled the Moscow file of Lee Harvey Oswald, JFK’s assassin, who had lived for three years in the Soviet union. After Nosenko’s defection in 1964 — a few months after Kennedy was shot in Dallas — he assured the CIA that the KGB had never tried to recruit Oswald, who was regarded as "too unstable" to be of use. It was a crucial moment in the cold war, an apparent intelligence breakthrough that may have prevented a nuclear conflict had America concluded that Moscow was behind the assassination. But what if Nosenko was a fraud. That tantalising possibility is examined in Spy Wars: Moles, Mysteries, and Deadly Games, by Tennent H Bagley, the former CIA case officer who was initially in charge of Nosenko’s defection. James Angleton, chief of the CIA’s counter-intelligence unit, went to his grave in 1987 suspecting that Nosenko was a double agent whose main task was to distract the agency from a KGB mole. "The book goes a long way toward rehabilitating [the idea] that Angleton was right in calling him a KGB plant," said Ron Rosenbaum, a New York journalist who spoke to Bagley earlier this year. Bagley, who now lives in Brussels, argues that the KGB’s aim was to steer the CIA away from realising that the Russians had recruited an American agent in Moscow in 1949 and perhaps two others later. The book raises the possibility that a KGB mole may have worked at the CIA during the cold war.