A fire that torched a couple's live-in motor home early Wednesday in a Santa Rosa Avenue motel parking lot was possibly sparked by a cigarette, said a Santa Rosa fire official.

The woman told firefighters she'd stepped out of their non-smoking motel room and into the nearby motor home for a smoke just minutes before the fire started, said Santa Rosa Battalion Chief Mark Basque.

"She thinks she may have discarded a match improperly or dropped an ash in the living area," said Basque.

At 1:42 a.m., 911 calls reported the motor home ablaze with flames coming out of the roof.

A Santa Rosa fire engine arrived one minute later according to dispatch reports. Motor homes, like mobile homes, burn quickly and firefighters found it engulfed in fire.

Because the flames threatened the motel, two Santa Rosa fire engines and a ladder truck and a Rincon Valley engine responded to the call and held the fire to the vehicle.

Basque said the 15-foot, older model motor home, which doubled as the couple's residence, was destroyed along with its contents.

The couple, whose names weren't available, were being aided by local Red Cross volunteers.