compartment before it spread to this car, then minutes later it was on the home. where s your hose at? reporter: a next door neighbor got the first video of the fire a couple minutes after it started. and his dad tried to alert the family still inside the home. the house is on fire. we called them out. they stayed in our house a little bit. reporter: the couple and two small children were not injured, but they could hear parts of their cars exploding as they burned next door. a man who lives down the block said it was the initial explosion that shook him. it sounded like a bomb went off, and then it just engulfed the cars. reporter: that was at about 2:00 in the morning. within minutes both cars were overcome with flames and fire had spread to the garage. normally a car would take a little bit to catch on fire. that car torched in three minutes, i mean it was torched reporter: contra costa arson investigators are looking into the fire and a spokesman for the