Arson has not been ruled out as the cause of a fire that consumed one Discovery Bay house, caused extensive damage to another and charred a third.

As of Wednesday, Contra Costa County Fire Inspector Ray Iverson said his investigators should have the cause of the fire pinned down within the next 24 hours.

"Our investigation team has been out there investigating the site and will be out there again today," Iverson added.

Lesley Belcher, her husband Steve and their two children (ages 2 and 5) were forced to flee their North Point house Sunday evening because it had become engulfed in flames originating from the house next door. Belcher said it wouldn't surprise her if the fire was an act of arson.

"The inspector of the arson squad told us, 'We have the stuff that we need,'" Belcher said.

She added that about six weeks ago, her neighbor told her his house had flooded after one of the toilets overflowed. There was supposedly so much water damage that the man began gutting his house. "The house was taken down to only studs - no windows. There were no contents; there was nothing in it."

East Contra Costa Fire Prevention District Chief Bill Weisgerber said he could confirm that there were no occupants in the house that burned to the ground, but couldn't verify the presence of any contents inside.

Weisgerber said that when the 5 p.m. fire call came in, Discovery Bay's engine was handling a medical call, and Brentwood and Byron's engines responded to the fire.

It became a two-alarm fire once personnel aboard the approaching engines saw how much smoke was showing.

"The fire got completely out of control before they (ECCFPD) arrived," said Belcher.

Weisgerber agreed, saying the battalion chief in charge told him, "He had never seen a house with fire coming out (everywhere).

"It was very difficult, very defensive from the get-go," Weisgerber said.

After about an hour and a half of battling the blaze, firefighters declared it under control. Officials estimated that the first house was a total loss, while the Belcher house received about 50-percent damage. The third house suffered minor exterior damage.

Between the three homes, Weisgerber estimated the damages at $1.1 million.