CHICAGO (CBS)–A Glenbard East High School student has been charged with posting a social media threat over the weekend that threatened a school shooting today.

The DuPage County Sheriff’s Office charged the student, 18-year-old Jairus Castillo of Glendale Heights, with one felony count of disorderly conduct–threatening violence at a school.

DuPage County

Police in west suburban Lombard said Castillo posted a photo of an unidentified person holding an assault rifle with the caption, “He’s shooting up the school Monday 3rd period after the bell.”

The threat shook the school community.

Patrick Brown was at the school Monday picking up his younger brother and said he didn’t know how to react.

“I would have been devastated to (get a) call and if something happened to my little brother I wouldn’t know what to do,” Brown said.

No one came to the door Monday at the Castillo residence when CBS 2’s Jeremy Ross stopped by to speak to the accused man’s family.

Castillo is scheduled to be arraigned on Nov. 19.