The driver of a bus that caught fire while carrying nursing-home patients fleeing Hurricane Rita (search) was charged Monday with criminally negligent homicide in the deaths of 23 passengers.

Juan Robles Gutierrez, a 37-year-old Mexican citizen, was taken into federal custody on an immigration violation (search) five days after the Sept. 23 explosion near Dallas.

Sheriff's spokesman Sgt. Don Peritz would not give any specific examples of any negligence by Robles, saying details will be released if he is indicted.

"The bus is under his care, custody and control, and so is everyone on board," he said. "Safe transportation from the nursing home to the final destination is his responsibility. Based on the end result, he failed in that responsibility."

There was no immediate comment from the bus company, Global Limo Inc., which was shut down by federal regulators Oct. 7 as a hazard the public. Its telephone has been disconnected.

Peritz said the investigation was continuing and additional charges could be filed.

Each of the 23 counts of criminally negligent homicide carries up to two years behind bars and a $10,000 fine.

The bus erupted in flames about 16 hours after leaving Houston. Some passengers and the driver escaped, but the flames, fed by 18 medical oxygen tanks (search), trapped many inside.

From the beginning, investigators focused on the condition of the bus brakes. A motorist told investigators he motioned the driver to pull over shortly after seeing a rear wheel hub that was glowing red.

Authorities said Robles did not mention the encounter with the other driver when they interviewed him after the fire.

Sheriff Lupe Valdez said investigators also found no evidence that Robles helped several people off the bus before it was engulfed in flames, which was widely reported after the explosion.

"After an exhausting number of interviews, we have been unable to confirm any of those claims," Valdez said in a statement.

However, Peritz said a failure to help crash victims was not part of the charges against Robles.

Robles did not have a lawyer Monday. The Mexican Consulate (search) said it would provide him with legal help.

The Texas Department of Public Safety has said that the bus' right rear brakes failed because of the loss of bearings, and that the left rear brakes were "not maintained in good working order."