A member of the US Navy was arrested after the pick-up truck he was driving plunged off a San Diego bridge, killing four people and injuring nine at a festival below, authorities said.
Authorities identified the driver as Richard Anthony Sepolio, 25, who was stationed at the naval base on Coronado Island across the bay from San Diego.
Sepolio was alone in the truck yesterday afternoon when he lost control and it hit a guardrail and fell 60 feet on to a vendor's booth at Chicano Park, California Highway Patrol officer Jake Sanchez said.
He was taken to hospital with major injuries and was later arrested on suspicion of driving under the influence of alcohol or drugs, causing deaths and injuries, the officer said.
"It's horrible. It's horrific. We had innocent people down here having a good time and now they're gone," Mr Sanchez said.
The California Highway Patrol identified the dead as a 62-year-old man and 50-year-old woman from Chandler, Arizona, and a 59-year-old man and 49-year-old woman from Hacienda Heights, a suburb east of Los Angeles.
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 pick-up truck with Texas licence plates landed on a vendor's booth set up for La Raza Run, a motorcycle ride that ends with a celebration at the park and typically draws hundreds of participants. The crash was steps away from a stage where a rockabilly band was playing.
"I saw a truck come right off the freeway. It was going so fast it flew over the stage and landed in front of the stage on a tent, a booth that was set up," Chase Dameron told The San Diego Union-Tribune.
He said four people in the booth were crushed by the truck.
"It was like a movie. It was like in slow motion," Dameron said. "Where it hit, there was dust and debris and instant chaos and panic. People running crazy."
Another witness said the truck hit the front end, bounced and landed on its side.
Photos from the scene show the truck's front end crumpled and its bonnet popped open.
The park is located beneath the bridge in a predominantly Hispanic neighbourhood in central San Diego.