When the FBI rang the doorbell of David Barnett's Bethesda home in April 1980, his wife Sarah was shocked. Her husband had been keeping her in the dark about some things. He'd put the $92,000 he got from the Soviets in a separate banking account.

Barnett worked for the CIA for 12 years, most of it posing as a U.S. diplomat in Indonesia.

He resigned in 1970 and set up an exporting business, but it foundered, and by 1976 he had debts of $100,000. That was when he approached the KGB in Indonesia. Over three years, he sold detailed information about CIA operations in Indonesia and the names of CIA informants.

In 1977, he went to Vienna, Austria, and was debriefed fully by top KGB agents. He told them everything he knew about the CIA, including insights on why Soviet SAM missiles had been unable to hit B-52s over Vietnam, and the names of KGB agents the CIA had tagged as potential recruits.

The Soviets ordered Barnett to get a job with the White House or a congressional committee, and he moved to Washington. But by then, investigators had a hunch he was spying. So the CIA rehired him to teach recruits about resisting interrogation -- to keep an eye on him.

U.S. agents spotted Barnett meeting the KGB in Vienna, Austria, in April 1980, and days after that the FBI came by his home. Three days later, his wife had a stroke while washing the family car.

He pleaded guilty to selling secrets to the Soviets and was sentenced to 18 years in prison.

Friends at the time of his arrest described Barnett as detached, aloof and unfeeling.

One described him as a man who "always looked like he had a secret."