Deputies with the Los Angeles County Sheriff's Department responded to the 5500 block of Whittier Boulevard just before 10 p.m. and found a 27-year-old man unresponsive, lying in the street.
The victim was taken to the hospital where he died. His identity has not been released.
Investigators say that the victim and another man got into an argument, exchanged words near a food truck, and the suspect pulled out a gun and opened fire. The victim also pulled out a gun and fired back, they say.
The suspect drove away westbound on Whittier Boulevard in a dark-colored pickup truck, according to detectives. The victim managed to run a short distance before collapsing.
The shooting is being investigated as gang-related.
Anyone with information regarding this homicide investigation is asked to call the L.A. County Sheriff's Department at (323) 890-5500, or Crime Stoppers at (800) 222-8477.