The incident happened as the 78-year-old victim was crossing the street at the crosswalk on Imperial Highway near the westbound ramp to the 91 Freeway.
A vehicle stopped when the man fell to the ground, but a second vehicle struck the man around 10:26 p.m.
The man was pronounced dead at the scene. No further information about the victim has been released.
An active search is under way for the first vehicle that sped off. The car is described as a small compact vehicle. Authorities say the car initially stopped but the driver later took off.