The family had learned from his girlfriend that D'Amato was a "swinger" who was cheating on her and attending "wild parties" where he engaged in homosexual activity with other men, sources said.

Consigliere Stefano Vitabile, former acting boss Vincent (Vinny Ocean) Palermo, soldiers Anthony Capo and Anthony Rotondo, and associate Victor DiChiara took part in a plot to dispatch D'Amato and dispose of his body so it would never be found, according to court records.

D'Amato's homophobic murder has become a heated issue at the upcoming loansharking/money laundering trail of Joseph Watts, (right) a Gambino gangster and longtime pal of the family's jailed-for-life boss, John Gotti.

Prosecutors don't want defense lawyers to question Capo, a key government witness, about the underlying reason for the murder for fear it may be so offensive to some jurors that they would ignore or discount Capo's testimony about Watts's loansharking.

Assistant U.S. Attorney Andrew Genser said the motive was irrelevant and "so

Andrew Weinstein, one of three lawyers representing Watts in the legal fight of his life, argued strenuously that the motive was essential to his defense but tripped himself up by saying that "nothing was worse than murder."

If nothing is worse than murder -- and Capo (right) will testify he was involved in several mob hits and many failed rubout attempts -- argued Genser, then there was no reason to bring up the homosexuality issue.

Brooklyn Federal Judge David Trager agreed with the prosecutor and ruled that defense lawyers could not bring it up during the trial.

After D'Amato's girlfriend lodged her complaints, Capo, 42, reported them to his mob superiors who satisfied themselves they were true and "that he had to go," said one source. "The order came down. It was open and shut. If a New York crime family ever found out, they would have lost all respect."

While Genser won his main battle, he lost a skirmish with the media when

D'Amato, a cohort of Gotti's who often visited his Little Italy headquarters in the late 1980's and 1990, was overheard on an FBI bug plotting to kill a DeCavalcante soldier who Gotti thought was a potential informer.

When FBI agents assigned to the Gambino family first spotted D'Amato at the Ravenite Social Club, they thought he was then-U.S. Senator Alfonse D'Amato, to whom he bears a striking resemblance.

Agents quickly discovered that Gotti's visitor was John D'Amato, and that he had no familial connections to the former Senator. They also learned that John D'Amato had occasionally passed himself off as Alfonse D'Amato's cousin, including one time when he was stopped for a traffic violation in Scarsdale.

As Gang Land revealed last month, Capo -- a fellow Staten Islander and onetime loanshark customer of Watts -- was tapped for Watts's trial to bolster the testimony of the prosecution's main witness, Gambino turncoat Dominic Borghese, whose first trial appearance against Watts ended in an acquittal.

Watts, 60, faces 20 years in prison if convicted. He also stands to lose $3.4 million he allegedly made from a huge loansharking business and invested in a luxurious beach hideaway on the Gulf of Mexico.

But one Gang Land reader found the contest so near and dear to his heart, however, that he was carrying a printout of it several weeks ago. And, who knows, he may still have it in his car.

On April 1 -- we're going to resist the temptation to make any April Fools jokes -- Staten Island cops stopped Gambino soldier Jerome (Jerry) Brancato and found a copy of a Gang Land column that featured an action shot by Daily News photographer Keith Torrie of Atlanta first baseman Andres Galarraga blasting a three-run homer in the third inning of a Braves' 6-4 win over the Mets on June 29.

Brancato, one of four wiseguys in the upper left hand corner of the above photo -- he's number 2 in the blowup at left -- had just left a breakfast meeting with a bookmaker at the Unicorn Diner at 2944 Victory Blvd.

Cops did not arrest Brancato, but during a search of his late model Oldsmobile, they saw the Gang Land column printout.

"You know Jerry Capeci?" said one.

"No," said Brancato. (right) "I think he knows me."