Lt. Craig Valenzuela says Bieber's car collided with the person at 11:45 p.m. Monday on Sunset Boulevard.
Valenzuela says nobody was cited or arrested and officers determined no crime was committed. He says investigators are trying to determine whether the pedestrian was in the roadway.
A video posted by TMZ.com shows Bieber getting into a Ferrari. He's surrounded by paparazzi and as the car drives off, one falls to the ground and grips his knee.
A request for comment from Bieber's publicist, Melissa Victor, was not immediately returned.