The suspect reportedly flashes a phony law enforcement badge in an effort to earn the trust of his victims.
According to police, a sixth grader at Lawrence Middle School in Chatsworth was walking home alone on Friday afternoon when a man approached her near the intersection of Independence Avenue and Vintage Street.
The man pulled out a fake badge, told her he needed to put a tracking device on her bra and then touched her inappropriately.
Another sixth-grade girl reported a similar incident when she walked home alone last month.
The school sent out a flier to parents informing them of the incident.
"I have my son that goes here, so that's really scary. I think I'm going to be picking him up all the time," said parent Maribel Orozco.
The suspect was described as a 20- to 22-year-old man, 5 feet 4 inches to 5 feet 5 inches tall, with short brown hair and brown eyes. He was last seen wearing a white T-shirt and blue shorts.
"I know there are a lot of tricks that some people use to talk to small kids, but I tell them they don't have to follow anyone's instructions except for us," said parent Jorge Barrera.
Officers say if you're worried about a cop being a fake, ask to see an identification card.
"We all carry identification. We're required to give a business card at the end of an investigation. Make sure that you ask for a business card. You'll certainly get one," said LAPD Sgt. William Sanders.
Police say more victims have come forward, and they are working on putting out a sketch of the suspect.
Anyone with information is urged to call the LAPD Devonshire detectives at (818) 832-0609.