Three Brooklyn high schools will have beefed-up security on Friday after threats of a shooting surfaced on Facebook.

The NYPD said Friday that they believed the threat is old, but they are taking all precautions in case and increasing security. According to NBC New York, parents had notified Edward R. Murrow, James Madison, and Midwood high schools after finding the threat online. The schools then contacted police, who investigated the threat.

Patrol cars are being stationed at all three of the schools. Parents of students at Murrow High School said the school contacted them with a robocall about the increased police presence.