Federal investigators sought clues Saturday in the burned-out remnants of a bus that exploded in a traffic jam and killed 24 elderly evacuees fleeing Hurricane Rita (search).

National Transportation Safety Board (search) spokesman Keith Holloway said investigators would analyze the wreckage for evidence on the cause of the explosion that killed residents of a Houston nursing home who were heading inland away from the storm.

Mark Cooper, a lawyer for Global Limo Inc. (search), the south Texas company that operated the charter bus, said Saturday that the company was "monitoring" the situation.

"We are and will continue to cooperate with the ongoing governmental investigation," Cooper said in a statement.

Witnesses have described smoke filling the bus cabin after it pulled over early Friday on Interstate 45 south of Dallas. The vehicle soon was in flames, and a series of explosions — probably medical oxygen canisters igniting — fueled the flames and trapped most of the occupants inside.

The 38 residents of Brighton Gardens nursing home had boarded the bus Thursday afternoon and were plodding inland for hours in heavy traffic caused by the hurricane evacuation.

"We wanted to take every precaution for our residents," said Meghan Lublin, a spokeswoman for the nursing home, explaining the decision to relocate Brighton's residents to a site in Dallas owned by the same company, Sunrise Senior Living.

"Moving forward, we're trying to work through this tragedy together," she said Saturday. "It's something we'll all think back to and one day we'll move on. But I don't see any of us really getting over this."

Lublin said grief counselors were available for survivors of the fire, including six employees who were aboard the bus.

Three people remained hospitalized Saturday. A Parkland Memorial hospital spokeswoman said two of those patients were listed in fair condition and one was in stable condition.

Holloway said he could not comment on a newspaper report Saturday that the 1991 model bus had an expired registration and might have been called into use only because of the emergency. The Houston Chronicle reported it was not among 10 buses registered with the state as being used commercially by Global Limo.

Another newspaper said Global Limo had a history of safety and financial problems. The Dallas Morning News reported the owners of the company filed for bankruptcy protection in February in a bid to block a takeover of the business for nonpayment of debt. The company's license also was revoked for a few days in May by federal authorities — the second time since 1993.

The Federal Motor Carrier Safety Administration also had singled out Global for full inspections when police stopped the company's buses, the newspaper reported. Global drivers were ordered to stop driving five times during the past 2 1/2 years after violations such as not having logs documenting how long they have been behind the wheel.

Cooper declined to comment on those reports.