Murder Mystery: Not a Question of Who, but Why : Crime: Both young men came from good families. They were at a drug- and alcohol-free party when an argument erupted. Later, one of them pulled a gun.

EAST SAN GABRIEL VALLEY —  No one disputes that Jose Aguilar shot and killed Damon Washington at nearly point-blank range during a teen “flyer party” in Diamond Bar last Nov. 30.

Aguilar, who is now on trial for murder, confessed the day after Washington’s death.

Even the reason for the shooting is known: Washington, black and 18, and Aguilar, Latino and 19, became embroiled in a racially tinged argument.

Still, a mystery remains:

How could two exemplary youths, both from good, loving families, never involved in gangs and crime, attending a party from which alcohol and drugs were banned, end up as the principals in a senseless homicide?

The shooting is “not characteristic of him at all, or the way he was raised,” church Pastor Dennis Corrigan said of Aguilar. “He is a very gentle boy.”

“He was good-hearted,” Sean Reed said of his longtime friend, Washington, the son of a police officer. “He was a good kid, an all-around kid.”

Yet, the two youths found themselves posing as tough guys at the party, a type of open-invitation gathering usually advertised through hastily drawn flyers that can draw hundreds of guests--including, authorities say, an increasing number of armed teen-agers and gang members.

Aguilar assumed Washington was armed and shot in self-defense when Washington appeared to go for a gun, defense attorney Mike Adelson said.

“Apparently, it’s common to have guns at these parties these days, unfortunately,” Adelson said during opening arguments in Pomona Superior Court last week.

The observation was borne out by Los Angeles County sheriff’s homicide Detective Loxi Hagthrop.

“More and more teen-agers are carrying weapons to parties,” Hagthrop said outside court. “They give all kinds of reasons for carrying them.”

But, the detective added, those parties are usually in gang-infested neighborhoods. The November party on Bregante Drive was in a solidly upper-middle-class area of Diamond Bar where homes sell for an average of $250,000.

About a dozen young men--including Washington--all friends from elementary and high school, helped plan the party. News of the event was spread by a flyer that opened it to all. Witnesses told detectives that gang members were among the nearly 200 youths who showed up.

Bryan C. Smith--who allowed his son, Kyle Davis, to hold the party in his home--testified that he did not know a flyer had been distributed. Smith said he helped set up equipment for a disc jockey, cleared the back patio for dancing, posted a “no alcohol” sign and stood at the door to charge $2 per person to help his son pay the disc jockey.

The admission fee was what Aguilar reportedly wanted to avoid when he and two friends jumped a concrete block fence and were immediately confronted by Washington. Witnesses told investigators that Aguilar resented being told to get in line and argued with Washington.

Meanwhile, Washington, a 5-foot, 11-inch football player, wanted to ensure that Aguilar, heavier and four inches taller, obeyed. To intimidate Aguilar, Washington reportedly put his hand to his waist as if he had a gun and said: “I hate (expletive) Mexicans.”

Aguilar left the party but returned with a gun, witnesses said. After saying, “So you don’t like Mexicans, huh?” Aguilar shot Washington, they said.

Deputy Dist. Atty. Pam Buscali said Aguilar’s actions indicate the murder was premeditated and deliberate, a reason to convict him of first-degree murder and send him to prison for 30 years to life.

But Adelson said his client had returned only to retrieve his wallet, which had fallen out of his pocket when he hopped the fence. Aguilar took a gun with him because he feared Washington, the defense lawyer said.

No weapon was found on Washington’s body.

Shocked and puzzled friends and family members of both youths say their backgrounds provided no clues to the tragedy.

Washington grew up in Diamond Bar, the son of veteran Los Angeles Police Traffic Officer Dennis Washington.

The officer made sure his son’s friends felt welcome at the Washington home. They lifted weights in the garage, swam in the back-yard pool and often enjoyed dinners at the home, said Reed, Damon Washington’s pal since childhood. Damon was the star fullback and captain of the Rowland High football team, and his parents attended every game, Reed said.

Low scores on college entrance exams kept Washington out of several big universities that had sent scouts to recruit him, so he went to Fullerton College, said his high school coach, Harry Robinson. Sidelined last year by an injury, Washington expected to shine at the community college this year, the coach said.

“His family was a real good family,” Reed said. “Now, I’ve seen Mr. and Mrs. Washington with that look on their face. You can see it in his eyes. . . . He’s lost half of his life.”

Aguilar’s family is similarly grieved and puzzled.

A graduate of South Hills High School in West Covina, Aguilar was enrolled at Cal Poly Pomona. But his main involvement for the past five years was home, family and church.

He divided his time between his parents, who were divorced 10 years ago, Corrigan said. As a member of The Carpenter’s Company church in San Dimas, Aguilar often accompanied his father to 6 a.m. prayer services and participated in church picnics and other gatherings of the 75-member congregation, the pastor said.

Aguilar was often described as a “gentle giant,” or “teddy bear,” Corrigan said.

Fred Aguilar said his son wanted to help children and often coached pickup basketball games at Shadow Oak park in West Covina.

It was loyalty and responsibility to his family that prompted young Aguilar to buy the 9-millimeter handgun that he used to kill Washington, his relatives and friends believe. Though members of his family did not know it, the youth bought the gun on the street to protect them, Corrigan said.

The clergyman called the purchase “a foolish act, but the motivation was self-defense.” He said, “Where he had lived, and because he is Mexican-American, he was in situations where he saw gang violence.

“And no one told him if you live by the sword, you die by the sword.”