The driver of a vehicle that barreled onto a sidewalk, killing a teacher and injuring eight young students, was arrested Wednesday, police said.

Laura Samayoa, 20, of Los Angeles, was booked for investigation of vehicular manslaughter with gross negligence and hit-and-run collision involving a fatality, authorities said.

She told police the crash was caused when her boyfriend grabbed the steering wheel during an argument, police Sgt. Brian Fitzpatrick said.

An attorney for the passenger, 19-year-old Reynaldo Cruz, said his client told him he didn't grab the car's steering wheel.

"He flatly denies that," attorney Peter Navarro told The Associated Press.

Samayoa and Cruz were being held on $400,000 bail. Cruz, who turned himself in late Wednesday, was booked on the same charges, said police Lt. Chris Maddox.

The students, whose ages ranged from 10 to 13, had just left a nearby school when the car barreled onto the sidewalk about 3 p.m., Maddox said.

Three children were in good condition at UCLA Medical Center and two were in fair condition, a hospital spokeswoman said.

Two other children were in stable condition at Brotman Medical Center, and one who had been admitted there in stable condition was later transferred to another facility, a spokeswoman said.

A witness said he was leaving work in the suburb just southwest of Los Angeles when he heard screeching tires. He said a woman he believed to be the driver tried to leave the scene but he stopped her.

"I looked across the street and I saw bodies flying, and the car literally pivoted around and came to a stop," Tennyson Collins told KCAL-TV.

Collins said the woman climbed out the driver's side window and began to run. He said he chased her.

"At first she said, 'I wasn't the driver.' And I said, 'You were in the car. You need to come back as a witness,"' Collins said.

The woman told Collins she couldn't go back.

"She said she had a 2-year-old child, and she was going to jail and was really scared," Collins said.

Los Angeles County coroner's Lt. John Kades identified the teacher as Carrie Philips but declined to release her age or other information.

Police said the teacher worked at Turning Point School, a private school that enrolls students from kindergarten through eighth grade.

A distraught woman who answered the phone at the school declined to identify the teacher or discuss the accident.