A member of the U.S. Navy is facing DUI and vehicular manslaughter charges after the pickup truck he was driving plunged off a San Diego bridge, killing four people and injuring nine at a festival below.

Richard Anthony Sepolio, 25, who was stationed at the naval base on Coronado Island across the bay from San Diego, was alone in the truck Saturday afternoon when he lost control and fell 60 feet onto a vendor's booth at Chicano Park, California Highway Patrol Officer Jake Sanchez said.

Sepolio remained hospitalized Sunday with serious injuries. His rank or job description was not immediately available.

"It's horrible. It's horrific. We had innocent people down here having a good time, and now they're gone," Sanchez said after the crash.

The people who were killed were Cruz Elias Contreras, 52, and Annamarie Contreras, 50, of Chandler, Arizona; and Andre Christopher Banks, 49, and Francine Denise Jimenez, 46, both from Hacienda Heights, a suburb east of Los Angeles, the San Diego County Medical Examiner said.

Witnesses had said four people in the booth were crushed by the truck.

Eight people on the ground were injured. One suffered major trauma, and seven others had minor to moderate injuries, said Lee Swanson, a spokesman for the city's Fire-Rescue Department.

Witnesses said the GMC pickup truck with Texas license plates landed on a vendor's booth set up for La Raza Run, a motorcycle ride that begins in downtown Los Angeles and ends with a celebration at the park. The crash took place steps away from a stage where a rockabilly band was playing.

On Sunday, mourners gathered at the park to lay flowers and candles and say prayers for the victims.

Tina Camarillo told the San Diego Union-Tribune she and her daughter were in a booth next to the one that was hit.

"To see such tragedy in an instant . . . ," she said. "(The truck) fell and all I saw was darkness, the glass blew, the canopy fell on my head. My daughter was running to get my mom. It was horrible."

Iris Jimenez, 29, told the newspaper she got out of the way just in time.

"I saw the truck coming at me, and if I hadn't run, I'd be dead," Jimenez told the newspaper. Her companion, Pedro Sanchez, was one of several men who rushed to lift the pickup off the victims.

Photos from the scene show the truck's front end crumpled and its hood popped open.

The park is beneath the bridge in a predominantly Hispanic neighborhood in central San Diego.