A Mercedes driver died and two passengers were seriously injured when the car left Highway 116 west of Guerneville and caught fire early Monday, the California Highway Patrol said.

The crash was reported around 12:17 a.m. near Redwood Drive. Investigators said the car was moving at an undetermined high speed when the driver lost control. It struck a rock and a tree before catching fire.

Firefighters put out the flames and found the driver dead inside the car. The two adult male passengers escaped and were taken to Santa Rosa Memorial Hospital with major injuries.

CHP had not released the identities of those involved. The cause remained under investigation Monday afternoon.