The Kern County Coroner's Office says the man killed in Poso Creek died of blunt head injuries.
The coroner's office released the cause of death for 21-year-old Michael Ray Eller on Wednesday morning.
Eller was in a car that left Round Mountain Road east of Granite Road, just north of Bakersfield, when it ended up in Poso Creek on Feb. 9.
A woman was also in the car at the time, but she was rescued.
The coroner's office has ruled the incident an accident.