Death Threat Made at Post-Prom Party, Witness Testifies : Courts: Defendant was angry after basketball star Berlyn Cosman told him to leave her hotel room, prosecution contends at start of murder trial.

Paul M. Crowder, a high school dropout accused of the post-prom slaying of basketball star Berlyn Cosman, had threatened to kill the athlete after she and another friend refused to let him party in the room where they were sleeping, a witness testified Monday at the opening of Crowder’s murder trial.

That alleged threat will form much of the basis of the prosecution’s charge that Cosman’s death was first-degree murder.

According to witnesses and the prosecution, Crowder, 19, a former Crescenta Valley High School football player, repeatedly waved a .357 magnum and drunkenly pointed it at students celebrating their prom in the early hours of June 1 at the Crown-Sterling Suites Hotel in Anaheim.

Deputy Dist. Atty. Christopher J. Evans said that during the evening, Crowder jokingly loaded and unloaded the revolver, held it on his lap, gestured with it, and pressed it into one teen-ager’s buttock, asking if he would like it blown off.

Several teen-agers who attended the party testified Monday that Crowder became angry after Cosman and a friend, Jill Cappillero, asked him to leave their room.

Mitchell Stroup, a 16-year-old who attended the party, testified that Crowder then left the main party room. About 20 minutes later, Stroup said, he heard Crowder yelling in the hallway.

“He was cussing, saying: ‘Then where am I gonna sleep? . . . I wanna party in here,’ ” Stroup said. “He walked back into our room cussing and mumbling under his breath . . . saying, ‘I hate those bitches. I’m gonna kill them.’ ”

Just before dawn, as Cosman, 17, slept on a fold-out bed, Crowder returned to the room and shot her, the prosecution alleges. The bullet passed through her head and lodged in the mattress.

Cosman, an aspiring Olympic basketball player at Crescenta Valley High who had won an athletic scholarship to a Missouri college, died soon afterward.

The defense contends that Crowder stumbled in the doorway to Cosman’s room, accidentally discharging the gun. Prosecutors argue that Crowder is guilty of at least second-degree murder because he should have known his actions were reckless enough to kill. When a gun is used, a murder charge carries a punishment of 17 years to life.

Evans said he intends to present an additional theory of first-degree murder, based largely on the statement Crowder allegedly made about hating Cosman and Cappillero and wanting to kill them. A first-degree murder conviction could mean 27 years to life.

“The evidence will show he went there (the hotel room) to shoot someone,” Evans told jurors in Orange County Superior Court.

The trial began Aug. 26, but was delayed while an appeals court considered a defense request for a postponement. That request was denied last week, so the trial resumed Monday.

A parade of teen-age witnesses described a typical prom-night party: About two dozen youths talked and played beer-drinking games in smoke-filled rooms while MTV blared on the television set. A few smoked marijuana or took LSD. They described some party-goers as “wasted,” others as “buzzed.”

Defense attorney E. Bonnie Marshall, who deferred an opening statement until later, focused on the drinking and drug use in her cross-examinations, implying that the witnesses might not be recollecting events accurately.

Questioning the homicide detective on the case, Marshall noted that most of the mattress in which the bullet was found has since been destroyed. She has said that that mattress could prove that the bullet was fired from close to the ground, supporting her theory that Crowder was falling as the gun went off.