Police believe speed and alcohol may have played a part in a deadly accident in Colma Monday morning.
Police say the driver of a green Mustang was heading north on Hillside Boulevard when he rear-ended a green Honda. The Honda went into a retaining wall and the driver is expected to be OK.
But the Mustang hit a different retaining wall and the car split in two, ejecting three passengers.
Police say three Daly City residents -- 22-year-old Rubin Vazquez, 21-year-old Jonathan Mouton and 23-year-old Rosa Falla -- all died at the scene.
Police say the driver, 25-year-old Paul Diaz, took off after the accident.
They believe he went to Falla's house in Daly City prior to turning himself into police.
Police from several agencies spent hours at the home on A Street collecting evidence.
Back at the accident scene, dozens of people who knew the victims showed up to remember their friends.
James Newton says he grew up with Mouton.
Newton says Mouton dreamed of becoming a mechanic.
"He accomplished that, he went to school and got all credentials to be a positive part of society," Newton says. "All he did was help people, fix cars."
Diaz was booked in San Mateo County Jail on felony hit-and-run and vehicular manslaughter charges.
An investigation on the fatal accident is ongoing.
NBC Bay Area's Jodi Hernandez contributed to this report.