SAN DIEGO -- A young man who allegedly drove drunk and was involved in a chain-reaction crash that killed a Marine and a young woman on Interstate 15 north of Escondido pleaded not guilty Thursday to several felony charges.

Oscar Tinoco, 18, faces two counts of gross vehicular manslaughter while intoxicated, hit-and-run and driving under the influence of alcohol causing injury, Deputy District Attorney Jodi Breton said.

According to the California Highway Patrol, the chain of events began about 4 a.m. Oct. 10 when a sedan rear-ended a Jeep Cherokee carrying four Marines near Gopher Canyon Road.

After the Marines got out of the Jeep, a car driven by Tinoco knocked one of the Marines off an overcrossing and onto Gopher Canyon Road, CHP Officer Eric Newbury said. lance Cpl. Robert T. Austin, 19, died in an operating room at Palomar Medical Center.

Tinoco and a passenger allegedly ran off, and an SUV driven by Sarah Garcia of Fallbrook slammed into the defendant's car and rolled down an embankment.

Garcia died at the scene. "One of the things that is tragic was the girl, Sarah Garcia, was celebrating her 22nd birthday and was one exit away from getting off the freeway," Breton said.

Tinoco's blood-alcohol level registered .08 percent, right at California's legal limit, more than two hours after the collision, meaning it was probably at .12 or .13 percent when he was driving, Breton alleged.

Judge Marshall Hockett set bail at $500,000 for Tinoco, a resident of Quail Valley in Riverside County.