A group of eight was driving home to Lake Elsinore from Universal Studios around 5 a.m. Saturday when their SUV was clipped by a newer-model white car, which then took off.
The SUV, driven by the wife and mother of those killed, rolled down an embankment and over an off-ramp.
Four people were pronounced dead at the scene and the other four were taken to the hospital. Police suspect they were not wearing seat belts.
Gerardo Herrera, 49, his 21-year-old daughter Noemi and 29-year-old son Luis, as well as 26-year-old Elba Rosales, were killed.
Rosales was the girlfriend of another of Herrara's sons, who was injured in the crash.