A hoax 911 call locked down Middlesex School in Concord on Thursday, Oct. 8, and temporarily closed Lowell Road while police searched for a nonexistent threat.

Concord Police, the Concord Fire Department, Carlisle Police and other area departments responded to the call, the Carlisle Mosquito reported. The school activated lockdown procedures while officers swept the entire campus. No threat was found.

Carlisle Interim Police Chief Andrew Booth confirmed that Officer Eric Koukos and K9 Athena assisted in the response, the Mosquito reported.

The tactic is called "swatting." A caller fabricates an emergency to trick dispatchers into sending a heavy police response to an unsuspecting location. The U.S. Departments of Education and Justice issued guidance to schools on Sept. 25 warning that such threats "often come in clusters" and that schools should be prepared to respond.

That pattern played out across the region in early October. On Oct. 2, Maynard Police responded to a hoax call at Maynard High School, according to the Mosquito. One day before the Middlesex School incident, three schools in New Jersey received similar calls. Westfield High School and Springfield Central High also reported swatting incidents this year.

Middlesex School has been targeted before. A swatting call on Feb. 14, 2023, drew officers from Concord, Acton, Carlisle, Lexington and Lincoln, along with the Concord Fire Department. That search also found no threat.

Swatting can violate multiple federal criminal laws, including statutes covering interstate threatening communications, false information and hoaxes, and bomb threats, according to the federal guidance letter. The letter stated that swatting "costs taxpayers millions of dollars in personnel and equipment, lost classroom time, and property damage."

The Mosquito's report did not mention any arrests or suspects in connection with the Oct. 8 incident.