Police identified a 52-year-old man as the suspect in the stabbing death of a 15-year-old girl on a high school campus in Stockton.

Anthony Gray was booked into the San Joaquin County Jail for investigation of murder, the Police Department said in a statement late Monday.

“Detectives believe this appears to be a random act and they are trying to determine why this student was targeted,” the statement said.

The girl was stabbed several times at about 11 a.m. Monday at Stagg High School and died at a hospital, Stockton Unified School District Superintendent John Ramirez Jr. said at a news conference. The girl’s name wasn’t immediately released.

The assailant attacked before security and staff could stop him, Ramirez said.

“We definitely will be re-evaluating” campus security, he said.

Online inmate information from the San Joaquin County Sheriff’s Office showed that Gray was being held without bail and was scheduled for a court appearance Wednesday afternoon. It was not known whether he had an attorney who could speak on his behalf.