ST. LOUIS (AP) _ Police said Tuesday they will seek a vehicular manslaughter warrant against a school bus driver who allegedly raced a car on Interstate 70 before the bus struck a signpost, killing one student and injuring 12.

Bus driver Mark Trice, 26, refused to submit to a breath test for alcohol after Monday's accident, but police obtained a warrant to test his blood for drug or alcohol content, Sgt. Fred Foan, a St. Louis County police detective, said Tuesday.

Foan said he had been ordered not to release the results of the tests, but added: ''The results are favorable for prosecution.''

Police will seek warrants Wednesday, Foan said. ''He is going to be in the hospital until Friday, so he's not going anywhere,'' he said.

One of the injured bus passengers said Tuesday he was ''screaming and scared to death'' moments before the school bus smashed into the signpost.

''We were screaming that he (the driver) was going to hit the pole,'' said Eric Washington, 15, a sophomore.

Washington, who was treated for minor injuries at DePaul Health Center, said Trice had been speeding and racing with a green Volkswagen. Police were seeking the driver of the car for questioning.

Foan said some students told police that before the crash Trice asked, ''Should we cut him (the driver of the Volkswagen) off?''

The bus was carrying pupils from Parkway North Senior High School to their homes in north St. Louis as part of the areawide voluntary school desegregation program.

Washington said that moments before the accident Trice tried to get the bus under control ''and he just couldn't do it.''

''I was scared to death I was going to die,'' he said. ''I just closed my eyes. I thought it was all over.''

''He wanted to pass the car and when he couldn't, he turned to us and asked, 'You want me to hit it?''' Washington said. ''Then he swerved and lost control of the bus and we hit the pole.''

The impact ripped the bus' passenger compartment from the frame. ''It looked more like an airplane crash than a traffic accident,'' Foan said.

Washington, who was sitting near the front of the bus, said Trice was thrown through the windshield.

Another student, Joyce Jones, 14, also said Trice was driving erratically. She said Trice ''started racing a car, a green Volkswagen, and he said 'Do you want me to run him over?'''

''He started swerving into another lane,'' she said. ''He didn't have control. He was driving real fast.''

Once the bus was on I-70, ''he really started flying, changing lanes and stuff'' Washington said. ''The bus was zigging and zagging.''

Lee Collins, a brother of Trice and a driver for the same bus company, R.W. Harmon & Sons, said Trice told him he was ''telling the kids to sit down. He looked around to tell them that, and to avoid hitting the Volkswagen, he swerved. That's when he hit whatever he hit.''

A lawyer for the bus company, Larry Davis, said Tuesday that he was investigating and would comment ''as soon as all the facts are determined.''

''There's been a lot of rumors and allegations,'' Davis said. ''I don't have enough information at this time to make a statement.

The St. Louis County medical examiner's office said Kimberly L. Bogan, 18, was killed. She had to be pried from the wreckage.

One student was in critical condition Tuesday at Normandy Osteopathic Hospital North with head injuries. Most of the other injuries were minor, authorities said.