ANAHEIM (CBS/AP) — Authorities have interviewed the driver of a California school bus that crashed but still don’t know what caused the bus to veer out of its lane, over a curb and into trees and a lamp post, injuring 12 people, a California Highway Patrol spokesman said Friday.

The driver gave investigators a brief statement late Thursday, spokesman Florentino Olivera said. He did not know what the driver told authorities.

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Olivera said one of the things the CHP is investigating is whether the driver passed out on the bus before the accident or if he has high blood pressure, which may have contributed to his condition.

“If he has a medical condition, that is very important to our investigation. If he does have one, then we’ll look into his medical condition, see if he’s taking any prescription medication – if he was supposed to take some and didn’t take any prior to getting into the bus crash,” Olivera told KCAL9’s Michelle Gile.

Investigators will also review surveillance videos from two on-board cameras, and they plan to inspect the bus next week. They will also interview witnesses, including one who said they bus may have been going 70 mph, Olivera said.

More than one student shared that the driver appeared to linger at a stop before the crash, causing them to question if he was feeling OK.

“He seemed to stay out at the last bus stop because he holds up the sign that lets people cross the street longer than usual. It usually takes 30 seconds but it took two minutes,” one student told Gile.

It was too early to determine if the driver could be subject to a criminal investigation, he said. There were no skid marks at the scene, and the CHP will try to determine if the brakes were working.

Two students and the driver remained hospitalized Friday, but they were expected to survive, Anaheim police Lt. Bob Dunn said.

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Three others with minor injuries were released from the hospital late Thursday and six more were treated at the scene.

The most seriously hurt in the Thursday afternoon crash was the driver, who had to be cut from the bus and pulled through the windshield before he was taken by ambulance to University of California, Irvine Medical Center, authorities said.

Student Jak Pintches, 14, said the bus went off the road during a turn.

“I flew out of my seat and hit the other side of the bus” and injured his back, the teenager told the Orange County Register.

Part of a tree went into the bus and cut a girl’s leg, he said.

After the crash, someone ran up and told everyone to get off because the bus was leaking gasoline, he said.

The bus was taking students home from an after-school activity at El Rancho Charter Middle School when it crashed next to Anaheim Hills Golf Course, said a statement from Michael L. Christensen, superintendent of the Orange Unified School District.

The bus was equipped with seat belts, police said, but it wasn’t clear how many of the students were wearing them.

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