At about 2:30 a.m. Saturday, Vasquez allegedly ran across lanes of traffic on the eastbound 10 Freeway east of Vermont Avenue. A car was driving about 60 mph and struck Vasquez. The driver remained at the scene and told authorities there was no way to avoid him.
Vasquez was pronounced dead at the scene, California Highway Patrol officials said.
Vasquez's injuries were so gruesome that family members say officers thought he was an older man, until identifying him as the missing freshman soccer player on Monday.
"We didn't have any way of identifying Mr. Vasquez at the time. He had no ID on him, his cell phone wasn't working, so there was no way of finding out who he was," CHP Officer Edgar Figueroa said.
On Friday, Vasquez drove down to Southern California with friends for a spring break trip.
His grandma, Bonnie Mongolin, says he didn't really want to leave his younger brothers.
"He just left really half-heartedly," she said. "I dropped him off at the BART station and he just said, 'I love you, nana,' and I said, 'I love you, Eloi,' and that was it."
Early Saturday morning, Vasquez left a party at the Tau Kappa Epsilon fraternity at USC, telling friends he wanted to walk to the beach. They tried to stop him, but he left anyway. His mother believes he had been drinking.
About an hour later, he made two phone calls to Aurora Cardenas, a friend in Berkeley. She says he sounded confused and asked for help.
"He was just really worried and didn't know what to do," she said.
Eventually he hung up and he was hit by the car just seven minutes later.
When Vasquez didn't turn up the next morning, a search effort was launched and a $100,000 reward was offered for information about his whereabouts.
"We are saddened to hear of the passing of Eloi Vasquez. We were coordinating with his family today to do everything we could to aid in the search efforts. Our thoughts and prayers are with Eloi's family and friends," Tau Kappa Epsilon released in a statement.
Vasquez finished his first semester with a 3.35 GPA, Vasquez's soccer coach Kevin Grimes said. Coaches and fellow players said he had a strong work ethic and considered him a strong player.
"Although he only spent a little over a semester here at Cal, his impact was huge, certainly on me. I really loved Eloi and I know our teammates did too," Grimes said.
Funeral arrangements were underway.
Sister station KGO-TV contributed to this report.