Months prior to the massive Thomas Fire that ravaged Montecito and surrounding areas, the Whittier Fire burned 18,430 acres in Santa Barbara County. Investigators have now determined that the Whittier Fire was started by a vehicle.

A passenger vehicle driving through tall grass on the hillside above Camp Whittier ignited the Whittier Fire on July 8 on Bureau of Reclamation land south of Highway 154 near Lake Cachuma, according to the Los Padres National Forest Service.

The wildfire quickly spread onto National Forest System lands in the Santa Barbara Ranger District. The blaze was not fully contained until Oct. 5

Authorities have not filed criminal charges, a Forest Service press release states. Forest Service officials say they are not releasing additional details of the investigation because of the age of the driver.

Investigators have yet to determine the cause of the Thomas Fire, which burned 281,893 acres, making it the largest wildfire in California history.