Trial Opens in Race-Charged Slaying of Youth : Crime: One of the white defendants threatened violence to black outsiders who visited his neighborhood, a prosecutor asserts.

The alleged ringleader in the murder of a black teen-ager in the predominantly Italian-American Bensonhurst section of Brooklyn warned his ex-girlfriend to stop inviting blacks into the neighborhood or he would blow their heads off, a prosecutor asserted Monday.

At the opening of the trial of two young men charged in the slaying last Aug. 23, Assistant Dist. Atty. James Kohler claimed that 19-year-old Keith Mondello made the threats to Gina Feliciano, who was planning to celebrate her 18th birthday on that day.

When Feliciano told Mondello that she would invite anyone she pleased to the affair at her mother’s apartment in Bensonhurst, Kohler said, Mondello recruited a gang of about 40 toughs who armed themselves with baseball bats and at least one gun.

They then attacked Yusuf Hawkins and three of his friends as they arrived in the neighborhood, by coincidence on the night of Feliciano’s party, to see about buying a used car, Kohler said.

The death of 16-year-old Hawkins last year heightened racial tensions in this city to their worst level in years and ignited a series of black-led protests, one of which erupted into a bloody clash with police at the foot of the Brooklyn Bridge.

“This was not the story of Romeo or Juliet and the feud between the Capulets and the Montagues or even the feud between the Jets and the Sharks in ‘West Side Story,’ ” Kohler said. “The evidence will show you that the motives for the murder were as callous and depraved as the act itself.”

But in his opening argument, Mondello’s attorney, Stephen G. Murphy, said that Feliciano--a key witness for the prosecution--fabricated her account of Mondello’s alleged role in the murder and has boasted of manipulating state prosecutors and her own attorneys for her own advantage.

Murphy contended that, in a taped conversation with her sister, Dawn, Feliciano “makes it clear that the truth has nothing to do with anything. She calls her mother a liar. She calls one of the cops a moron.”

He also claimed that Feliciano and her mother, Phyllis D’Agato, were smoking marijuana in D’Agato’s apartment on the night of the slaying and that neither could be relied upon to give accurate testimony.

“They are filthy, contemptible liars,” he said. “And what’s the really sad part, is they have polarized this whole damn city . . . They’re a real team, those two.”

Murphy described Feliciano as a drug abuser who has never made any serious attempt at rehabilitation. “She is still the same drug addict she always was and she always will be,” he said.

Mondello and Joseph Fama, 19, the alleged triggerman in the Hawkins slaying, are the first of eight white Bensonhurst men charged in the fatal shooting to go to trial.

Mondello and Fama have been charged with murder, riot, assault, menacing and numerous other crimes. They face penalties of 25 years to life imprisonment on the murder charge. Five of the six other defendants also are charged with murder.

Hawkins’ mother, Diane, sat with family members in the packed Brooklyn courthouse. She was moved to tears by Kohler’s account of the slaying of her son.

“As the young black men were standing, looking at house numbers (in their search for the household advertising the used car), this gang surrounded them,” the prosecutor said. “They demanded to know what they were doing in the neighborhood--as if they needed a passport.”

Hawkins was surrounded, four shots were fired and “two of the shots struck Yusuf Hawkins in his chest and pierced his heart, and Yusuf fell to the sidewalk,” Kohler said.

In his opening statement, Kohler acknowledged that a black Bensonhurst resident, Russell Gibbons, helped round up the baseball bats the gang wielded and was even invited to join them on the night of the slaying.

Murphy said that Hawkins and his family deserve sympathy, but he said that Feliciano--and not his client--is the one who should be blamed for what happened to the youth.

Murphy said that Hawkins’ three friends will testify that no racial epithets were hurled at them and that one of the three was “so unconcerned with this whole thing that he was reading the newspaper clipping (with the car ad) and wasn’t even paying attention.”

In an unusual courtroom arrangement, the two young men are being tried simultaneously in the same courtroom but with two separate juries--one for Mondello and one for Fama--because Mondello allegedly has implicated Fama as the gunman.

State Supreme Court Justice Thaddeus E. Owens, the presiding judge, ordered the tandem jury setup as a way of saving time in trying the cases. Though different, each jury includes seven whites, three blacks and two Latinos, and represent an economic cross-section of Brooklyn neighborhoods. The juries sit one behind the other in the courtroom.

Opening arguments in Fama’s case were scheduled for today because of his lawyer’s illness on Monday.

The trial of the two is expected to take three or four weeks.