damien shows us the damage. >> reporter: the cars were in the long term parking lot, several destroyed by a mysterious fire. the car owners, they could be half a world away not knowing their car is charred. the cars were parked next to each other in what administrators call a cluster. just after midnight, a parking attendant noticed the fire and sdiledd dialed 911. preliminary reports tonight show signs of arson, but if they determine the fire was no accident, the sheriff's office will begin a criminal investigation. six cars were destroyed. a seventh parked nearby was damaged by the heat. sfo says the parking lot does have surveillance cameras, but not at the location of the fire. they say the incident is all very unusual. >> right now we don't know. that's what the fire department wants the arson team to look at because it's highly unusual for a car parked in an open air lot on a cool damp night to ignite on its own. so they want it find out what cause this had fire. >> reporter: sfo has to look at dmv records for those vehicles. they'll use that information to notify the owners. no