CHICAGO (CBS) — Police officers were keeping a close eye on a south suburban junior high school, after learning of a Facebook threat targeting students.

Officials at Rickover Junior High School in Sauk Village said they are taking the threat very seriously.

It all started when parents noticed a threatening post on a student’s Facebook page. The Rickover student allegedly threatened to “kill everyone during seventh period.”

Parents saw the post and alerted school officials. A text message blast was sent out to all parents, alerting them of the incident.

Community Consolidated Schools District 168 school board member Sharon Davenport said she talked to the parents of the student involved, and they claimed their son’s Facebook page was hacked.

“It was found by some of the other children on Facebook, and so they started telling their parents, and then they told one of our board members, and our board member gave that information to our superintendent, and he immediately called the principal and the police,” Davenport said.

Davenport said increased security would be at the school on Monday. It was unclear if the student involved in the alleged threat would be at school, or possibly had been disciplined.