Investigators fear there may be more victims, and by Wednesday morning, they received four more tips about possible additional victims.
Detectives began an investigation when a girl confided in a friend, who then told an adult, that she had been sexually assaulted by Michael Downs.
"During the investigation we asked her if she knew of anybody else, which is typical of our investigation, and she gave us another name, which led us to another girl, and so forth and so on, until we identified the 14 we currently have," said Los Angeles County sheriff's Lt. Carlos Marquez.
The alleged victims are between the ages of 12 and 16 and attend three high schools and three middle schools in the Santa Clarita Valley.
"Some of the girls he told he was 16, others knew he was 19, but it was all done through social gatherings, either at parties or social events throughout the city or through Facebook," Marquez said.
Downs befriended the alleged victims on Facebook, gaining their confidence by giving them the names of other teen girls and saying he was friends with them. Marquez says Downs would ultimately convince them to meet with him and then allegedly had sex with them.
The alleged assault happened at several locations throughout the Santa Clarita Valley within the last year.
"It appears that students within the district were victims. However, we're not aware of the details or who those students are, and they're minors. We might not know exactly which students were impacted," said Gail Pinsker with Hart School District.
Since Downs' arrest made headlines Tuesday night, investigators say some of the victims have been receiving threatening and intimidating messages on Facebook.
"On some of them, it's just been name-calling, and calling the girls certain names, and others, it's been an actual threat of some kind of violent act towards the victim," said Marquez.
Downs attended Bowman High School, an alternative school that enables young adults to finish high school. Friends say they're stunned by the news.
"Definitely not the guy to do that. Definitely not that guy, because we would have talked about it. He would have told either me or one of my other friends. So I don't believe it at all," said Downs' friend Shane Davis.
Downs faces 29 sexual assault charges. He was arrested Dec. 15, accused of committing lewd acts with a child and having unlawful sexual intercourse.
He's being held on $1.8 million bail. He is due back in court in January.
Authorities are urging other possible victims to speak to police.
"We would like all victims to come forward in this. that would be the best situation possible," said Pinsker.
Anyone with information is asked to call the /*Los Angeles County Sheriff's Department*'s Special Victims Bureau at (866) 247-5877.