CHICAGO (CBS) — Students at a County Club Hills high school will see increased security on Monday after someone threatened a violent attack at the school.

Hillcrest High School alerted parents by email saying the school had learned about a threat, after it was posted on Facebook.

The superintendent told CBS 2 someone threatened to use a gun at the school. Police were contacted and they believe the threat is not credible.

Out of caution, County Club Hills and Hazel Crest police will patrol the school on Monday while classes are in session.