The incident happened around 11:30 p.m. Thursday near the Cirque du Soleil Kooza set-up on the beach. It happened on a portion of the beach that doesn't have any barriers.
Officers were flagged down to a silver Infiniti SUV stuck in the sand, and that's when they found a woman wedged underneath the car.
The victim died at the scene before she could be pulled out. Her age or identity has not been released.
The driver of the Infiniti, identified as YuYang Sun of Arcadia, remained at the scene. Authorities said he was reportedly driving in circles at high speeds on the sand when he ran over the victim.
"We were just passing by walking our dog and I saw that car stuck out there... but I saw the car door open... and it looked like there was a bunch of people running away from that car, at first, so I wasn't sure what the hell was going on," said Shyler Compton, who was in the area at the time.
The driver was later arrested for DUI, reckless driving and gross vehicular manslaughter.