Three more cars were torched in west Contra Costa County over the weekend, bringing to at least 14 the number of vehicles that have been set on fire since Wednesday, authorities said Monday.

The most recent fire was reported at about 10:50 p.m. Saturday, when someone set a car ablaze in front of a home on the 5500 block of Oak Knoll Road in El Sobrante, sheriff's spokesman Jimmy Lee said.

At about the same time, the Contra Costa County Fire Protection District put out two other car fires in Richmond, Lee said.

Investigators have at least one possible suspect in the rash of fires, a source close to the case said, but have not made any arrests.

Eleven cars were set on fire early Wednesday in El Sobrante, Richmond and San Pablo. No one has been injured in any of the fires, but one of the blazes damaged a window to a home, said engineer Rico Rincon, a Richmond Fire Department spokesman.

"That just shows how close it was to threatening the home," Rincon said. "Obviously, there's potential for further damage than the vehicles."

Investigators told Steve and Elaine Ziem, whose car was torched Wednesday in El Sobrante, that whoever was responsible may have broken into the vehicles first and searched the interiors for combustible material.

Among the cars burned Saturday was the 1996 Toyota Camry belonging to Antoinette Holmes, 57, of El Sobrante.

"It's frustrating and shocking to look out the window to see your car on fire," Holmes said.

Holmes' neighbor Walter Hamner, 63, said he and his wife had turned off the lights to go to sleep when they realized that there was still a bright light outside.

The flames from the Camry were "shooting up about 7 to 8 feet above the car," he said.

"This is absolutely insane," Hamner said. "We have somebody out there that really has a problem."