William Holden Bell, an engineer with Hughes Aircraft Co. in Los Angeles, was an easy victim for spy recruiters, Pentagon officials say.

"Ripe for recruitment," a recent Defense Investigative Agency report concluded.

For Bell, 1976 was a terrible year. He divorced his wife of 29 years, and, facing alimony of $200 a week, declared bankruptcy. His 19-year-old son had died in a camping accident the year before. And at work he'd been shunted to a second-rate job.

That was when he met Marian Zacharski, a Polish businessman in the same apartment complex. The two hit it off, playing tennis and socializing frequently.

In 1978, Zacharski sought Bell's advice in making contacts at Hughes. Bell helped out, and Zacharski paid him $5,000 as a "consultant." Then he got Zacharski such items as the company's in-house newsletter. At some point, Zacharski started asking for classified material. That was what one FBI official later called Bell's "dividing line."

Zacharski was an operative of Polish intelligence assigned to get high-tech secrets.

Bell, who worked on tank radar, told authorities he never discussed with Zacharski what really was going on. But by 1979, Bell said he realized he was committing espionage. He told authorities he may have made as much as $470,000.

For more than a year, Bell photographed documents at work and took them to Polish agents in Europe. The material dealt with such subjects as NATO air defense systems and radar systems in U.S. tanks and F-15 jets.

He told officials that at a meeting with a Polish agent in Innsbruck, Austria, he received a veiled threat. "He told me that I had a lovely family. Then he said that . . . if anybody got out of line, that he'd take care of them."

In over his head, Bell confessed to FBI agents in June 1981. They had been alerted because of the company's suspicions about his foreign trips.

Cooperating with the FBI, Bell wore a recording device to a meeting with Zacharski, who was later arrested. Zacharski received life imprisonment, but last month the United States swapped him and three other East bloc spies for 25 persons associated with the West.

Because of his cooperation, Bell was sentenced to only eight years in prison.

In a recent study, defense officials concluded that Bell "felt genuinely trapped" by the threats, his need for money and the charm of Zacharski, who "worked with extreme caution and practiced subtlety."

"There is little left of my life now," Bell told a Senate committee recently. "But I feel I am freer in prison than I was with Zacharski."