GLENDORA >> Police arrested a 19-year-old, who is an apparent creepy clown enthusiast and former student of Sierra High School, in Glendora on Wednesday on suspicion of making threats against his alma mater, as well as toward the city of El Monte, authorities said.

William Salazar is accused of making criminal threats through Instagram and Facebook accounts dedicated to clowns, Glendora Police Chief Tim Staab said.

Students at Sierra High School began receiving posts from the account Tuesday night which threatened violence, Staab said. Students notified parents and school administrators, who contacted police Wednesday morning.

“Sierra skool gonna get hit (tomorrow) say your blessing #(expletive)skooliwasaclassclown,” read on of the posts.

“Bout to kill (expletive) in el monte whoever outside better know how to throw dem hands or shoot #ittimetoshowweanitclowingaround,” read another grammar- and spelling-shirking post.

The Facebook page, which was started on Monday, features pictures and videos of menacing-looking, sometimes ax-wielding clowns.

The Instagram account had been taken down Wednesday afternoon, however the Facebook page remained online.

Investigators soon determined the identity of the alleged poster.

“We tracked him to a relative’s house in Kern County,’ Staab said.

Salazar was expected to be booked on suspicion of making criminal threats and held in lieu of $50,000 bail pending his initial court appearance.

The suspect indicated to detectives that he authored the posts as a joke, but Staab said he found no humor in it.

“These types of threats are taken seriously by law enforcement, and if you make a threat against somebody, there’s a good chance you’re going to get arrested,” the chief said.

The online threats came as creepy clown-inspired hysteria spread across the nation in recent weeks, with sightings of sinister-looking clowns who are sometimes reported to try to lure children.

California had remained largely untouched by the clown-related shenanigans until Wednesday, when social media posts announced the jarring jesters could be expected to pay visits to Los Angeles County, including Pasadena, Whittier, and other Southern California communities.