Yuri I. Nosenko, 81; KGB Agent Who Defected to the U.S.

Claire George, a former CIA deputy director of operations who worked in the Soviet division at the time of Mr. Nosenko's defection, said yesterday that the handling of Mr. Nosenko "was a terrible mistake." But George added, "You can't be in the spy business without making mistakes."

Yuri Ivanovich Nosenko was born in 1927, in Nikolayev, a Ukrainian town on the Black Sea.

His father, a naval engineer, rose to minister for shipbuilding under Soviet leader Nikita Khrushchev, while his mother arranged for private tutors to school Mr. Nosenko in classical Western literature from Virgil to Voltaire. He developed an attraction to western culture.

Mr. Nosenko served three years in naval intelligence after his 1950 graduation from the State Institute of International Relations in Moscow. He then became a leader within the KGB's Soviet internal security division.

According to Tom Mangold's "Cold Warrior" (1991), a book about Angleton, Mr. Nosenko's KGB career specialized in following U.S. agents posted in the Soviet Union and in recruiting turncoats from foreign intelligence services. Mangold's book said he also oversaw blackmail operations.

Mangold asserted Mr. Nosenko eventually grew angered by what he considered hypocrisies of the Soviet system and signaled to U.S. intelligence agents his wish to defect on ideological grounds.

He made his first successful contact with U.S. intelligence in 1962, pleading desperation after squandering KGB funds on alcohol. He asked for $200 to repay the money. He later admitted this was a fabrication, and his request later raised doubts within the CIA about his intentions. Would he really sell out his country for $200?

But his propensity to drink was not a lie, and he was fully loaded when he met CIA officials in Geneva, where he was accompanying a diplomatic mission. He revealed key information about Soviet moles working in the embassies of Western nations as well as Russian intelligence methods. According to Mangold, he pinpointed 52 microphones planted inside the U.S. embassy in Moscow and how the Soviets avoided detection of the listening devices.

But his most stunning revelations were about Oswald, notably how the Soviet agency felt Oswald was too unstable mentally to be of much service.

None of this saved Mr. Nosenko from a bitter fate. Golitsin stoked Angleton's increasing paranoia about double agents in the CIA and the veracity of defectors, and Mr. Nosenko soon began his 1,277 days in custody.

After Mr. Nosenko's rehabilitation, he looked up the disgraced Angleton's number in the phone book in 1975 to confront him.

It was a brief and fruitless exchange, with Mr. Nosenko rising in his passions and Angelton cool and adamant about his judgment.

"I have nothing more to say to you," Angelton said.

"And Mr. Angelton," replied Mr. Nosenko, "I have nothing further to say to you."