NEW YORK — Sean "Puffy" Combs may be worth $400 million, but he haggled over a bar tab and stiffed his cocktail waitress, the woman testified Wednesday at the rap mogul's gun possession and bribery trial.

Barmaid Monica Caban couldn't shed much light on the 1999 nightclub shooting that landed Combs in jail, but her turn on the stand proved embarrassing nonetheless. The former Club New York employee told jurors Combs became annoyed when she presented him with the bill for $4,000 of imported champagne she'd poured for him, girlfriend Jennifer Lopez and the rest of their V.I.P.-area entourage.

"I was told I wasn't getting a tip because none was left for me," said Caban, prompting a chorus of defense objections. State Supreme Court Justice Charles Solomon struck her answer from the record as irrelevant, but the packed gallery was already chuckling.

Outside the courtroom Wednesday afternoon the defense camp quickly put out the word that Combs had indeed left a tip, but club personnel had failed to pass it on to Caban.

The trial, in its second day, may cost Combs much more than his reputation for generosity. He faces 15 years in prison if convicted on three counts of weapons possession and one count of bribing a witness. He is accused of firing a semiautomatic handgun during a scuffle in the club and then bribing his driver to take the rap when police found the gun in his customized Lincoln Navigator. Combs is being tried with his protege, rapper Jamal "Shyne" Barrow, who is accused of attempted murder, and bodyguard Anthony "Wolf" Jones, also facing gun and bribery charges.

The lively testimony of Caban, a college junior with her brown hair in a ponytail and wearing a three-quarter-length black leather jacket, stood in contrast to the dry, crime scene evidence that occupied the bulk of the day.

New York City Police Detective Edward Wallace, who examined the crime scene for nearly 14 hours after the Dec. 27, 1999 shooting, told jurors that ballistics and blood evidence are consistent with Combs and Barrow firing their weapons in the crowded club. Three people were shot. Although none of the injuries were life-threatening, two of the victims still carry bullet fragments in their bodies.

The crime scene analyst, however, admitted that the prosecution's hypothesis was only one of many possible scenarios and not "scientifically certain."

Combs, the CEO of Bad Boy Entertainment, scowled after prosecutor Matthew Bogdanos asked Wallace to make a series of assumptions about where people stood in the large nightclub, who did the shooting and the size and build of the shooters.

"Assume, assume, assume," said Combs, shaking his head derisively as he left the courtroom for the lunch recess.

The detective walked jurors through the layout of the club, reducing the hotspot of throbbing hip-hop music and flashing lights to washed-out snapshots and a large black and white schematic propped up on an easel.

Wallace showed jurors how he found evidence of at least five bullets fired near the club's main bar. One fragment, he said, matched the 9-millimeter gun found in Barrow's waistband after the fracas. The detective showed jurors close-up photograph of a hole in the ceiling which Bogdanos suggested was made by Combs firing a 9mm pistol straight up in the air.

Combs isn't charged with attempted murder, and the prosecutor seemed to try to check any attempt by Barrow's attorneys to suggest Combs, not their client, might be responsible for some of the injuries. Wallace said the hole's angle would make it impossible for the bullet to ricochet and strike the gun shot victims if they were standing where Bogdanos' indicated.

The exact location of anyone at the time of shooting is impossible to determine from the crime scene, Wallace acknowledged. More than 50 people were crammed into a bar area the size of a jury box, and when the shots rang out, hundreds rushed from the club. Wallace said the shell casings and bullets they did recover could easily have been kicked from their original location. Other evidence, he said, may have been carried out accidently in the chaos.

The fluidity of the crime scene is likely to become an important defense issue, especially because of two mystery bullets found in the club. Wallace said the deformed bullets, found near a chair in the corner of the bar, are from a 40-caliber gun, a weapon none of the defendants is accuse of possessing. Marks on the ceiling indicate the bullets were fired upward and then ricocheted to the chair area.

In his opening statement, Bogdanos said there is no way to tell when the bullets were fired in the club, but said they are unrelated to the crime. But Barrow's attorney, Murray Richman — who said unnamed "jealous" assailants attacked his client at the club — pointed out that someone could have walked from the club with a 40-calibre gun following the shooting and crime scene technicians would never have known.

Caban, who testified she hid behind the deejay booth when the gunshots rang out, gave jurors a sense of the atmosphere at the club. She described how her manager knew Combs' was going to stop by the club's weekly "Hot Chocolate" party and cleared her schedule so she could devote herself to waiting on him and his friends.

She said he and Lopez drank Veuve Cliquot champagne and danced, surrounded by security guards, on the club's main floor. It was a party scene, she said, and everything seemed normal, including Combs' dancing.

"He didn't bust any moves, as they say," Combs' lawyer Johnnie Cochran asked.

Giggling, Caban replied, "No, just dancing."

Testimony began Wednesday as it ended on Monday (the trial was not in session Tuesday)— with lawyers fighting bitterly over the testimony of Combs' bodyguard Curtis Howard. The defense charged that Bogdanos improperly attacked the credibility of Howard — his own witness — and moved somewhat half-heartedly for a mistrial.

Solomon denied the motion, but not before Bogdanos took another swipe at Howard, calling him an egregious liar who told one story to the grand jury and a second one more beneficial to his boss to the court.

"This is not about gamesmanship...this is a search for truth," Bogdanos said, prompting Combs' lawyer Benjamin Brafman to glance at the clock above the jury box. "I thought we'd wait until 3 or 4 before Mr. Bogdanos got all wound up," Brafman quipped.

Brafman tried to rehabilitate Howard with an extremely friendly cross examination. Howard testified that in his five years of working for Combs, he'd never seen him with an illegal gun and "I would never have associated myself with him."

To explain Howard's inconsistencies and perhaps to play on the jury's sympathy, Brafman asked him about his ongoing treatments for cancer. Howard said he had been forced to retire from his job as a corrections officer and claimed that forgetfulness was one of the disease's side effects.

Thursday's witnesses are expected to include more club employees.