Christopher Ng was arraigned in Ventura County Superior Court Wednesday on charges he sexually assaulted three females ranging in age from 13 to 41 years old.
Police believe there may be other victims who had contact with Ng through social media.
A father, who wished to remain anonymous to protect his daughter's identity, says his eighth grade daughter was targeted by Ng on Facebook.
"He started asking to talk to her, and where do you live, and such as that," he said.
He says his daughter was smart enough to break-off communications with Ng when the Facebook conversation grew profane.
"Words that you probably cannot, you know, put out on the news were used against my 13-year-old, and, yeah, it got pretty bad," he said.
Simi Valley investigators say Ng sexually assaulted a woman on Nov. 22.
During their investigation, detectives discovered two other sexual assaults linked to Ng. They fear there may be many more sexual assaults that haven't been reported.
Police say Ng used different online names, including "Chris Pastrana", and contacted numerous other girls through Facebook.
"It used to be in my day that you don't talk to strangers. These days the kids are talking to strangers all the time and they've never met them," the father said anonymously.
He says he's committed to consistently checking his daughter's social media interactions. He says it's the best way to make sure something like this doesn't happen again.
"She didn't become an ultimate victim of this guy, but I wonder how many other kids are victims of this guy, and they're not telling their parents because they're afraid to, or maybe haven't told the whole story to their parents," he said.
Ng's bail was set at $500,000. He is due back in court in February.
The investigation is ongoing. Anyone with information related to the case is urged to call the Simi Valley Police Department at (805) 583-6248.