Los Angeles authorities say they are investigating a report that Justin Bieber head butted a man during an argument at a Sunset Strip restaurant.
The Los Angeles Sheriff's Department says a witness reported seeing Bieber fighting with two bartenders at a West Hollywood restaurant and then head butt a patron early Saturday morning.
The department says Bieber and the bartenders had left by the time deputies arrived. The restaurant was not named.
The patron allegedly hit by Bieber had no visible injuries and did not file a police report.
But an investigation proceeds in case the person wants to pursue a case later.
Email messages sent to Bieber representatives were not immediately returned.
Cleveland police are investigating Bieber after a Las Vegas man reported the singer punched him in June.