Updated

A 17-year-old Beverly Hills boy accused of beating a prep school classmate with a claw hammer as they sat in his Jaguar must remain in a psychiatric hospital, a judge ruled.

A juvenile court judge on Friday refused to order the teenager removed from the hospital where he was admitted after being taken into custody Monday. He was charged as a juvenile with attempted murder and assault with a deadly weapon.

The boy, whose name was not released because of his age, attacked a 17-year-old girl who also attended exclusive Harvard-Westlake School as they sat in his car on a Studio City street, authorities said.

The girl's mother, Barbara Hayden, told the Los Angeles Times her daughter was struck 40 times with a claw hammer, breaking her nose, shattering her leg and splitting open her scalp in several places.

"Her hair and face were caked with blood," Hayden said. "On the left side, her head was shaped like a football."

Hayden said her daughter told her that before pulling the hammer from a backpack her classmate said he had thought about committing suicide.

The boy's lawyer, Patrick Smith, said his client was troubled but declined to elaborate.

After her attacker hit her several times, the girl's mother said, he pulled her from the car by her hair and continued assaulting her until the hammer broke. Then he began to choke her until she bit his finger.