Second Precinct Crime Section officers responded to Old Field Middle School, located at 2 Old Field Road, after a student allegedly made a threat of mass harm on May 13.
A school official notified police about the threat on May 17. The school searched the teens locker. She was arrested at the school at approximately 4:30 p.m.
The teenager was charged with Threat of Mass Harm, a Class B Misdemeanor, and will be arraigned in Suffolk County Family Court on a later date.