PROFILES : 2 Class Stars: 1 Ends Up a Victim, Another a Suspect : Stuart Tay was an outspoken nonconformist. Robert Chan was quieter, an academic decathlete.

Stuart Tay and Robert Chan seemed destined for academic successes beyond their many high school achievements. As honor students, they both excelled in extracurricular activities, were interested in computers and had dreams of attending Princeton University.

But the quest for higher knowledge has come to a tragic end for Tay, 17, who was murdered New Year’s Eve, and has been put on indefinite hold for Chan, 18, who is accused of his slaying. In addition to being scholars, police contend, the two youths were aspiring computer thieves.

On Tuesday, homicide investigators said that Tay, Chan and four other teen-agers were scheming to pull off a computer heist. But Tay was bludgeoned to death by his partners when they suspected he was not committed to the robbery and that he had lied to them about his name, police said.

And while the district attorney prepared to file murder charges against Chan and his four juvenile alleged co-conspirators, students and faculty members at two different high schools were shocked by the news about their fellow classmates.

“This is really hard to digest,” said Joan Casper, who taught honors English to Tay at Foothill High School in Santa Ana.

At Foothill High, students observed a moment of silence for Tay. Teachers said Tay, a senior, loved to provoke academic discussions in class and challenge teachers. They described him as independent and serious in schoolwork.

“There wasn’t a day that he didn’t speak out in class,” Casper said. “He would often play the devil’s advocate on an issue.”

Tay was in four honors classes and one advanced placement course that could have earned him credit for a college subject.

Casper said Tay was “a young man searching for answers, like all adolescents. He was a thinker and would provoke other people to think. He added vitality to the classroom. . . . He was not a maladjusted social outcast,” Casper said.

Marilyn Reardon, Tay’s honors history teacher and faculty adviser in the Junior Statesmen of America club, also spoke highly of his intellect.

She said the news of his involvement in something criminal “seems so doubtful. This is a boy whose parents adored him, and he had everything. . . . I always found him honest and trustworthy.”

Tay’s classmates also remembered him as an extremely intelligent young man with a special gift for computers. But they also saw another side of him, describing him as “rebellious” and “nonconformist.”

Tay was a keyboard player in an alternative music band. He also apparently liked to speed around the campus parking lot in a Mercedes-Benz convertible, and more recently in a red Nissan 300ZX.

Some students said that Tay wore an electronic pager and liked to give the impression that he had connections and was someone to reckon with.

Ernie Halter, an 18-year-old senior who had known Tay since the seventh grade, said that he respected Tay’s intelligence, but knew he had a “tendency to be very arrogant and very cocky. I knew he had a tendency to (upset) some people, and I think he just (upset) some of the wrong people.”

But most of all, people remembered him as a computer genius. Police, in fact, said that a mutual interest in computers led Tay to Chan and the others arrested for his slaying.

At Sunny Hills High School in Fullerton, where Chan, also a senior, and the other four teen-agers were enrolled, the administration on Tuesday closed the campus to reporters and television crews. But some students said that Chan was also an excellent student who earned awards in last year’s grueling academic decathlon.

Chan was in advanced placement calculus. He was also part of a five-member academic decathlon team from Sunny Hills that went to Singapore last March after winning an “Ambassadors to Singapore Competition” sponsored by Singapore Airlines and administered by the Los Angeles Times in Education Program. The team members were quizzed on their knowledge of current events and Asian culture.

Chan also ran unsuccessfully for president of the Student Coalition Club, a campus environmental group.

But unlike Tay, Chan apparently was soft-spoken in class.

In addition to his reputation as a scholar, Chan was known by some to be a tough individual.

One student, who identified herself only as April, said Chan and his friends often boasted that they were affiliated with a Chinese Mafia-like gang that claimed members among the students at Sunny Hills, Buena Park and Fullerton high schools.

“He was the type of guy you are polite to and don’t mess with,” April said.

Also contributing to this story was staff writer De Tran.