Huntington Beach Police say Jackson Westermeyer, 18, never showed his face or used his name when he allegedly committed his crimes.
"Many of those kids were threatened and coerced into providing more images and other things to our suspect," said Huntington Beach Police Chief Robert Handy.
At a Thursday news conference, detectives said they identified at least 10 victims between the ages of 11 to 15. The investigation began after the parent of one alleged victim attempted to set up a meeting with Westermeyer.
"The suspect came to the meeting and then left. The meeting actually didn't take place, but they were able to get his license plate number," said Handy.
Police say Westermeyer used various social media apps and sites to make contact. They believe there may be an additional 50 to 100 still-unidentified victims.
Police are asking parents to looks at their children's history on their electronic devices for the username Westmeyer used: "KATKAT7777." They say he used that on the social media site Kik to lure his victims.
Investigators say he also posed as a girl using the alias "Jesse."
"And then once he got enough photos of girls, then he turned to posing as a girl to get photos of boys," said Handy.
Westermeyer, who is facing 12 felony counts, was released on $200,000 bail.
"My client has never had any face-to-face or physical contact with anyone," said Scott Well, Westermeyer's defense attorney.
Because Huntington Beach Police believe there are still more victims, they are asking anyone with information to contact Orange County Crime Stoppers at (855) TIP-OCCS.