SOMERVILLE, N.J. — Jayson Williams cursed at a chauffeur just before he shot him, a close friend of the former NBA star testified at his manslaughter trial Monday.

Kent Culuko said Williams was holding an open shotgun down at his side in his master bedroom when he turned toward driver Costas "Gus" Christofi and called him a "motherf---er."

Then Williams snapped the barrel up, closing the weapon and leveling it at Christofi, Culuko testified. It discharged immediately, he said.

"He went like this," Culuko said, swiveling in the witness chair to face the jury box and raising his arm up from his side, "and the gun went off."

Culuko, a one-time professional basketball player in Europe and South America, was the first eyewitness to the shooting to testify against Williams, and the Somerset County Superior Court was filled to capacity for the first time in the trial's three week's of testimony.

Eighteen of Williams' supporters, including three retired NBA players, packed two benches behind the defense table reserved for his friends and family.

Culuko, who testified as part of a plea deal with prosecutors, undercut defense suggestions that Williams was aiming the double-barreled shotgun away from houseguests on Feb. 14, 2002. Defense attorneys claim Christofi unexpectedly entered the room from the opposite direction and walked into the path of an accidental shotgun blast.

Culuko said Christofi went into the room with Williams and three members of the Harlem Globetrotters and was standing still when Williams "turned 180 degrees" toward him. Christofi rolled his eyes, he said, and Williams called him the profanity.

Culuko said Williams had his hand on the rear part of the gun, but he did not know if was on the trigger.

Jayson Williams grimaced at times during his friend's testimony.

Culuko also said he saw Williams look down between the time he turned toward Christofi and shot him. That could be important testimony for the prosecution because it suggests Williams looked into the gun and may have known it was loaded before he flipped it toward the chauffeur.

The most serious charge against Williams, aggravated manslaughter, requires prosecutors to prove he caused Christofi's death through recklessness that manifested "extreme indifference to human life." If convicted of that and other charges, Williams, 36, faces 55 years in prison.

The defense contends the shooting was an accident and not a crime.

The Globetrotters are expected to testify later in the trial.

Echoing the testimony of others at the mansion that night, Culuko said Williams wiped his prints from the gun and made a crude attempt to stage the scene to look like a suicide. Culuko said Williams then directed him to wipe down the gun again and put it in a different spot. Culuko said he complied.

Williams' lawyers have suggested he was so distraught and shocked by Christofi's death that he may not have known what he and others were doing. Culuko, however, said that as police officers combed the scene trying to determine what happened, Williams, corralled with other witnesses in the dining room, stretched out on the floor and fell asleep.

"He was snoring," Culuko testified.

He said that, immediately after the shooting, Williams told the group of 11 visitors and his brother, Victor, "we should all say we were downstairs," and Christofi "must've come upstairs and shot himself."

Culuko testified he told police detectives the phony story, but later that day took a trooper aside and told him Williams was the shooter.

"I was trying to protect Jayson," he said of the false accounts he gave authorities. "I didn't want the story to come out."

For his role in the cover-up, Culuko was originally charged alongside Williams with evidence tampering, witness tampering and hindering apprehension. He agreed to cooperate with prosecutors and testify against Williams. In exchange, prosecutors dropped the hindering charge and allowed Culuko to enter a pretrial diversionary program that will eventually allow his record to be expunged.

On cross-examination, defense lawyer Joseph Hayden suggested Culuko had changed his account of the shooting to be more incriminating of Williams because he wanted prosecutors to accept his plea deal.

Culuko admitted that he was worried about going to prison and the harm a criminal record might do to the youth basketball camps he runs, but insisted he was testifying truthfully.

Hayden pointed to a letter Culuko wrote to a lawyer a month after the shooting saying he had only heard, but not seen the shooting.

"I kept telling people I heard the shot [so that] I would not have to be in the position I am today testifying against my friend," he said, jabbing at the witness stand and then gesturing to Williams at the defense table.

Culuko also admitted talking last week with Dean Bumbaco, a friend and fellow key witness for the prosecution. He said Bumbaco apologized for testifying last week that Culuko would "push his grandmother in front of a bus to make two bucks."

He claimed, however, that the only other conversation they had about Culuko's testimony was when Bumbaco advised him to know his police statement "word for word."

Before the shooting, Culuko, 31, was one of Williams' constant companions. The pair met when Culuko, a point guard, tried out unsuccessfully for Williams' teams, the New Jersey Nets, in 1997.

Culuko said he stayed overnight at the athlete's 40-room mansion three to five times a week and Williams gave him the security codes to his front gate and door. He said he and Williams planned to go in to business together and were scouting venues for a basketball camp.

Hayden read from a faxed message Culuko wrote to Williams the day before the shooting. In it, he writes "you are the best, Jay," and thanks Williams for "changing my life."

Culuko also played in pick-up games and charity events organized by Williams. Moreover, many of the men seated in the courtroom benches reserved for the defense supporters were Culuko's former teammates on those squads.

Asked at one point by Hayden to describe the players on those teams, Culuko said quietly, "Most of the guys in this courtroom" and stared into his lap.

First Assistant Hunterdon County Prosecutor Steven Lember later asked him to count the number of former teammates in the courtroom.

"Eight or nine," he said, squinting toward the back of the court.

During breaks in his day-long testimony, Culuko huddled with his parents and fiancé while his former teammates stood together in the hall outside the courtroom. As Williams entered, they greeted him with hugs and hand shakes.

He appeared stoic throughout most of Culuko's testimony, but at times, he grimaced.

Among Williams' supporters were former New Jersey Net Walter Berry, who also played for Williams' alma mater, St. John's University; Anthony Avent, who played for the Los Angeles Clippers and San Antonio Spurs; and Williams' Nets teammate Eric Murdoch.

Outside the courtroom, Berry said he had difficulty believing Culuko's account.

Williams "has been a perfect citizen from the times I've known him. I just can't believe what I'm hearing," Berry said, who added he has known Williams for 20 years.