In addition to the cars that burned, five other vehicles were found with their doors and trunks open, Rohnert Park Department of Public Safety Sgt. Wulff Reinhold said.
The first car fire was reported at about 3 a.m. in the driveway of a home in the 1000 block of Camino Coronado. The fire spread to an adjacent vehicle and up a palm tree, Reinhold said.
When officers found a second pair of vehicles burning in the 900 block of Camino Coronado four minutes later, firefighters from the Rancho Adobe and Rincon Valley fire protection districts were summoned, Reinhold said.
Suspecting arson, all Rohnert Park public safety officers not fighting the fires searched the area, Reinhold said.
Officers found five cars with their doors and trunks open outside nearby homes, Reinhold said. Nothing appeared to be missing from the cars, he said.
The fires were extinguished by 3:25 a.m. All four vehicles were a total loss and damage is estimated at $50,000, Reinhold said.
The homes where the fires occurred sustained scorching damage, Reinhold said.
Anyone with information is asked to call the Department of Public Safety at (707) 584-2600.