A member of the U.S. Navy arrested after the pickup truck he was driving plunged 60 feet off a San Diego bridge, killing four people and injuring nine at a festival below, will likely be arraigned this week at a hospital, authorities said Tuesday.

Richard Anthony Sepolio, 25, is expected to be arraigned Wednesday on charges including DUI and vehicular manslaughter, said district attorney's spokeswoman Tanya Sierra.

Sepolio remained hospitalized three days after the GMC pickup crashed through a concrete retaining wall and crushed a vendor's booth at Chicano Park, said California Highway Patrol Officer Jake Sanchez. He didn't know Sepolio's condition.

Sepolio had been stationed for about a year at the base on Coronado Island across the bay from San Diego, the San Diego Union-Tribune reported Monday (http://bit.ly/2eePzq6 ).

He enlisted in September 2014 and went to boot camp at the Recruit Training Command Great Lakes in Illinois and also attended apprenticeship schools in Pensacola, Fla., and Norfolk, Va.

Sepolio worked at Coronado as an aviation electronics technician, or a J130, and was assigned to Helicopter Combat Squadron 6. Aviation electronics technicians troubleshoot and repair a number of electronics in Navy aircraft.

A military spokesman said it is too soon to say what next steps the Navy will take.

"The Navy is supporting the investigation as they can, and we can't speculate from there," said spokesman Brian O'Rourke.

Blanca Sepolio, the man's mother, said family members didn't wish to comment on the crash when reached by the newspaper.

Saturday's crash happened as a crowd gathered for La Raza Run, a motorcycle ride that begins in downtown Los Angeles and ends with a celebration at the park. The truck crashed into a both steps away from a stage where a rockabilly band was playing.

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.

When he was 19 years old, Sepolio was arrested in Texas on suspicion of possessing or delivering drug paraphernalia. He was jailed on $600 bail. It's unclear how the case was resolved.