SAN DIEGO -- Four Perris High School seniors killed in a crash on Interstate 15 in Escondido while heading to a Mission Beach outing in May were under the influence of marijuana or alcohol at the time of the accident, according to the county medical examiner's office.

The results of the toxicology tests involving the teens were reported Wednesday by The Press-Enterprise of Riverside.

Three of the students died May 30 when the 1993 Acura Integra they were in flipped over and struck a tree on the side of southbound I-15 immediately north of the ramp to Highway 78, the California Highway Patrol reported.

The impact shot the car some 20 feet off the roadway, killing three of the boys on impact. The fourth boy was taken to Palomar Medical Center in Escondido, where he died the following day of his injuries.

Highway Patrol authorities said the car was traveling at 90 mph or faster and possibly racing another car before the crash.

Highway Patrol Officer Eric Newburg said investigators concluded that speed and driving under the influence of marijuana were the primary factors in the crash.

San Diego County medical examiner's toxicology reports showed that driver Javier Aguayo, 17, had recently used marijuana but that no alcohol was detected.

Passenger Pablo Hernan Ruiz, 18, had recently used marijuana and his blood-alcohol level was 0.08, the medical examiner's office said. Passengers Anthony Cash O'Neil, 17, and Jose Julian Espinoza, 18, had also recently used marijuana, and Espinoza had a blood alcohol level of 0.057, the coroner's report said.

The legal blood alcohol content in the state is 0.08.