Updated

A UCLA student charged with slashing a classmate's neck during a chemistry lab brought a concealed, six-inch kitchen knife into the class and stabbed the woman five times, police said Tuesday.

Damon Thompson, 20, was charged with unpremeditated attempted murder for the unprovoked attack on a female student standing next to him.

Los Angeles police Detective Alan Behnke said authorities were unable to determine a motive or whether the victim had been chosen at random. The woman, whose name was not released, was in good condition after spending time in intensive care.

Behnke said Thompson was cooperative but declined to speak to police.

"He hasn't clarified what his motive was," the detective said.

Several people witnessed the attack, and a teaching assistant and a professor were able to stanch the blood flow by applying pressure to the victim's neck.

Witnesses told police Thompson walked calmly into a student information office and told a staff member he had stabbed someone.

Thompson and the victim had no known relationship other than working in the same class.

Police found the knife at the scene of the incident — a lab on the top floor of a building in the heart of the university on the west side of Los Angeles. Behnke said the attack lasted about 15 seconds, with the woman stabbed three times in an arm and hand and once each in the back and neck.

Thompson was due to be assigned an attorney at his arraignment Tuesday afternoon. He was being held on $1 million bail.

UCLA history professor Stephen Frank told the Los Angeles Times that Thompson wrote several e-mails last year complaining about classmates making offensive comments while he was taking a written exam.

Frank said he was present during the entire exam and saw nothing to support Thompson's complaints.

Thompson's relatives have said he is an only child who left his mother's home in Belize two years ago to attend UCLA.