The crash occurred in the McClure Tunnel, where the 10 Freeway meets the Pacific Coast Highway.
One of the cars burst into flames, killing a 19-year-old from Bell.
Officers say the teen was intoxicated when he slammed his car into a guardrail and a wall.
The car then struck two other vehicles. Two others in the car managed to escape without serious injuries.
Several lanes of the 10 Freeway had to be shut and traffic was diverted onto 4th Street. All lanes have since reopened.
There was no word on what caused the crash.