As the star witness against crooked politicians trapped in the 1980 Abscam sting, Mel Weinberg came across as a likable con man. Weinberg, 58, coaxed seven members of Congress into accepting bribes, some in front of hidden FBI cameras. But last month his swashbuckling image was tarnished and his testimony in the Abscam trials impugned by allegations from his wife, Marie, 50. A bitterly unhappy woman who was demanding a divorce, she claimed that Mel took $45,000 in payoffs from one Abscam defendant and gave away expensive suits and furniture to FBI agents.

Now Marie Weinberg is dead. On Jan. 28 her body was found on the staircase of a vacant condominium next to her own in Jupiter, Fla. She had apparently hanged herself. A note left on the kitchen table read: "My sin was wanting to love and be loved, nothing more. But [a] campaign is being made by Mel to discredit me. I haven't the strength to fight him anymore.... Everything I have attested to is the truth."

Before her apparent suicide, Marie mailed her lawyer, Michael Dennis, a 19-page memorandum expounding on her charges. There is no trace so far of a mysterious 1980 diary that Marie called "my insurance policy." She said it was Mel's, but he testified under oath that he kept no such record during his dealings with the FBI that year. Marie said she had the diary hidden "somewhere very safe." Also believed missing are dozens of tape recordings that Weinberg made secretly of his conversations with FBI agents.

Marie's accusations against her husband were made in the course of an appeal by Florida Rep. Richard Kelly, a convicted Abscam defendant. The federal prosecutor was ordered to respond by Feb. 16. Meanwhile attorney Dennis, who also represents Kelly, is making the most of her charges. He also flatly refuses to call Marie's death a suicide. "I don't believe for one moment that she would take her own life," he says. The lawyer concedes, though, that Marie did attempt to hang herself once in 1959.

According to her friends, Mel's constant threats to have her declared an emotionally unfit mother to their 16-year-old adopted son, Mel Jr. (called J.R.), may have led to her suicide. Weinberg wanted custody of the boy, and now, of course, he has it.

For the last two years Mel maintained one home with Marie and J.R. and another, 15 miles away, with his British-born mistress, Evelyn Knight. The homes had identical wallpaper and furniture. "I'm a creature of habit," Mel joked. It was not until last October that Marie faced the reality that her marriage was a sham. Earlier she had asked Mel if there was another woman. "He kissed me," she told a friend, "and said, 'I love you, only you.' "

Weinberg admitted Knight's existence to his son, but claimed she was an FBI agent. In fact, she was his alleged accomplice in a phony 1977 international investment scheme that bilked singer Wayne Newton and others. After being tried and convicted, Weinberg agreed to cooperate with the FBI and eventually to take part in the Abscam caper. Weinberg once even conned his wife into unknowingly washing Evelyn's Lincoln Continental. When the car was waxed and gleaming, he traded it in that afternoon for a new Cadillac—for Evelyn. Marie was driving an Audi.

When Mel finally realized divorce was inevitable, he persuaded Marie to delay her suit for three months so as not to jeopardize a proposed deal involving an Abscam film starring John Belushi. Weinberg showed more irritation than grief over his wife's death: "She was a cuckoo," he announced. Even as his sobbing son received friends at a Tequesta, Fla. funeral chapel, Mel stood outside smoking a cigar, bantering with an FBI agent. Later Weinberg talked Marie's Seventh-Day Adventist pastor, Richard Duke, into conducting a hasty funeral, neglecting to tell Duke the casket did not contain Marie's remains. Her body was still in a county morgue, according to police officials. "I wanted to get it over with for the kid," Weinberg explained.