A fire that started in a man's pocket, critically injuring him and destroying his hotel room was not ignited by a cell phone as initially suspected, phone technicians said.

Nokia Corp. engineers found that the charred device still worked Wednesday and convinced fire department investigators that it had not spontaneously ignited in Luis Picaso's pocket.

Picaso, 59, remained in critical condition at the UC Davis Medical Center with second- and third-degree burns to his upper body, right arm and right leg.

"The phone still works even though it's burned," Vallejo fire inspector Bill Tweedy said. "If the phone had shorted out, it wouldn't have turned on."

The residential hotel and a ground floor business sustained about $75,000 damage in Saturday's fire.

The fire apparently started in Picaso's pants pocket while he slept on a plastic lawn chair in his room, authorities said. The flames set off sprinklers and an alarm, which alerted firefighters.

Picaso, who is under heavy sedation and has only spoken to investigators once, does not seem to remember what happened, Tweedy said. The investigation concluded without determining the cause of the fire.