LIBERTY, MO. ? The driver of a Liberty school bus that plowed into two vehicles at a busy intersection on Monday had pointed out problems with the vehicle’s air brakes at least twice in the months before the fatal crash, school officials confirmed Wednesday.

John Collum, an attorney for bus driver Irma Denise Thomas, said problems with the brakes — not driver error — are to blame for the collision that killed two men and sent 23 children to area hospitals.

“There were documented problems with brakes on that bus over the last couple of months,” Collum told The Kansas City Star. He said he based his conclusions on documents and a conversation with Thomas.

Liberty School District Supt. Scott Taveau has said Thomas told him immediately after the wreck that she could not stop the bus.

The crash killed David M. Gleason, 53, of Kansas City, and David Sandweiss, 49, of Liberty. Only two of the injured children remained in the hospital Wednesday night, officials said, at least one still in critical condition. The family of the second child has requested that the condition not be released.

Thomas, 45, still was in Liberty Hospital on Wednesday night.

School officials said two work-order requests Thomas filed, one in March and the other in April, raised concerns about a warning system that alerts drivers when air pressure for the brakes is low. Both times, a district maintenance employee found the system to be working.

Assistant Supt. Kent Peach said Thomas made a pre-trip inspection Monday morning that showed the warning system was working. Nothing in the bus’ maintenance records, he said, “is screaming that we had a problem for a long time, and we had a bus accident because of it. I don’t see that at all.”

An inspection by the Missouri State Highway Patrol last month found the bus to be in good condition, officials said.

Federal investigators with the National Transportation Safety Board said Wednesday it could take as long as 18 months to know what caused the crash. They also said a video camera on board the bus did not record the accident.

Taveau said the last recording from the device was on April 26.

The bus was one of a dozen in the school district that were repaired after a massive recall five years ago because of serious brake malfunctions.

The recall was prompted in August 2000 when Bendix Commercial Vehicle Systems of Elyria, Ohio, announced there was a malfunction in the anti-lock braking system. The problem was discovered after a school bus in San Francisco had a temporary loss of braking power.

At the time, Bendix said heavy trucks, transit buses and school buses built with the defective braking system could experience brake failure for up to four seconds at speeds of 20 mph and slower.

“This could result in extended braking distances and a possible crash,” the recall warned.