LAWRENCE (Mercer) — Threats made against six New Jersey schools in three communities on Friday are believed to be connected, according to this township's police chief.

Threats were made against two public schools and the private Lawrenceville School here, Linden High School, and County Prep and McNair Academic High School in Jersey City.

Police Chief Brian Caloiaro told The Trentonian that the threats to all the schools were made from a similar phone number that could not be traced.

After a series of threats made against schools last spring following a shooting at the high school in Parkland, Florida, state Attorney General Gurbir S. Grewal issued a directive requiring districts and local law enforcement to share information immediately about such threats.

Suspicious activity must be reported to the county terrorism coordinators and the state Office of Homeland Security and Preparedness (NJOHSP), which, in turn will immediately share such reports with the FBI.

The NJOHSP has not yet returned messages asking if this directive was followed.

Township police said a male called the office at the Benjamin Franklin Elementary School around 10:35 a.m. and said six pipe bombs were in the building. The building was evacuated. A caller to the New Jersey 101.5 newsroom said a pipe bomb threat was also made to the Lawrenceville School.

The Lawrenceville Elementary School was locked down after an adult male said he was headed to the school with a rifle. The other schools in the district, as well as Notre Dame High School and St. Ann's School, were also locked down.

Linden High School was placed on a lockdown while a search of the school was conducted by the Union County Bomb Squad and K9 unit. Normal activity continued at the school but no one was allowed to enter or leave.

The two schools in Jersey City were evacuated and later deemed safe, according to police spokeswoman Ashley Manz.