Youth Denies Role in Slaying of Student : Court: Hearing will be conducted to determine whether minor should be tried as an adult in death of Robert Sapinoso.

A 17-year-old denied charges Thursday that he played a role in the killing of a UC Irvine engineering student as prosecutors sought to have the youth treated as an adult.

A Juvenile Court commissioner ordered the Orange teen-ager to remain in custody on a suicide watch pending a hearing later this month to determine if the case should move to adult court.

“You are definitely a threat to the community,” Superior Court Commissioner F. Latimer Gould said as he ordered the youth to remain in Juvenile Hall.

During a brief hearing, the teen-ager stood next to his distraught mother, who sobbed in court, a handkerchief covering her head from a TV camera in the courtroom. The commissioner also appointed a defense attorney, who requested that the youth be placed on suicide watch because he is depressed.

On Wednesday, a second defendant, Vinh Quoc Ta, 18, of Santa Ana, was charged with murder and a special circumstance that could make him eligible for a death sentence in connection with the killing of Robert Sapinoso of Westminster.

The 19-year-old victim, a computer whiz nicknamed Zap for his lightning-fast typing, was shot to death Aug. 17 in Garden Grove as he and a friend tried to write down the license plate number of van they believed had been involved in neighborhood vandalism days earlier.

The juvenile faces the same murder charge and special allegation of lying in wait, but is not eligible for the death penalty because he is a minor. The juvenile also is charged with the attempted murder of the victim’s friend and allegations that he is involved in a gang and that a handgun was involved in the slaying.

Deputy Dist. Atty Vickie Hix said Garden Grove detectives are trying to determine who pulled the trigger and said the investigation is continuing.

“We expect to get a few others in custody,” she said.

The attorney representing the juvenile could not be reached for comment.

The two defendants were arrested last week in Boston while riding in a van that authorities identified as the one used in the killing.

The victim and his friend, a 20-year-old Cypress College student, had been following the van and trying to jot down its license plate number when the shooting occurred. The two had nearly finished writing down the number and were stopped at a traffic light when someone in the van got out, walked to their car and opened fire, killing Sapinoso. The friend was unharmed in the shooting and later gave police a detailed description of the gunman.

The juvenile is eligible to be tried as an adult in the slaying because of the seriousness of the charges against him.