The alleged encounter took place around 10:30 p.m. Monday at Sherman Oaks Castle Park, which offers miniature golf as well as batting cages. The incident was not reported until Tuesday.
Around the time of the alleged robbery, Bieber posted a video on Instagram showing himself playing miniature golf.
LAPD detectives interviewed the alleged victim Tuesday night. The incident involved a cellphone, an LAPD official said. Bieber was not arrested.
This is the latest in a long string of incidents involving the pop star. Last month, Bieber was detained by Customs for more than five hours at Los Angeles International Airport.
He is facing charges for allegedly driving under the influence and street racing in Miami. He's also dealing with assault charges in Toronto for allegedly attacking a limo driver. He's also being investigated for an alleged egging incident in Calabasas.