The shooting unfolded just after 9:30 p.m. Sunday at a small fair in the Pacoima area.
Police say it all stemmed from an argument between two men.
At one point, the suspect pulled out a gun and shot a 19-year-old, who is expected to survive.
Video obtained by Eyewitness News from a viewer who was riding the Ferris wheel at the time shows a bird's-eye view of the crowd moments after the shooting occurred.
You can see people running once shots were fired.
It's unclear what led to the argument. Meanwhile, the shooter has not yet been found and no arrests have been made.
Anyone with information is urged to contact police