Police have identified a 52-year-old man held over the fatal stabbing of a 15-year-old girl on a California high school campus.

Anthony Gray was booked into the San Joaquin County Jail for investigation of murder, Stockton Police Department said late on 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 Stagg High School and died in hospital, Stockton Unified School District superintendent John Ramirez Jr said at a news conference.

The girl’s name was not immediately released.

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

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

Online information from San Joaquin County Sheriff’s Office showed that Gray was being held without bail and was scheduled for a court appearance on Wednesday afternoon.

Stockton is a Central Valley city about 60 miles east of San Francisco.