Denville police and school officials were notified at 7:35 a.m. that an "act of violence" was going to occur at the E. Main Street school, Capt. Jeffrey Tucker said.
An investigation and search of the campus that began as buses were arriving determined the threat was not directed at the school, the email said.
Classes resumed with law enforcement on campus for the rest of the day.
Several North Jersey tech schools had lockdowns Friday morning for precautionary measures, local police told Daily Voice.
A screenshot of an indirect threat made Thursday at Passaic County Technical Institute in Wayne resulted in an increased police presence Friday, Prospect Park Mayor Mayor Mohamed T. Khairullah said.
Butler and Parsippany schools had an increased police presence for precautionary measures, parents said.
Bergen County Tech and Parsippany Hills High School were in lockdown mode briefly, during which a PHHS student tried jumping out of a first floor window around 9:55 and cut himself, police said. He was treated by EMS. Both schools resumed classes.
Garfield High School students and staff were sheltered in place Friday morning after police were tipped off to what was described as "a threatening post on social media."
Morris County Tech students posted videos from the inside of the dark building on Snapchat saying there had been a shooting threat. Parents confirmed the threat on social media saying police were not letting any incoming buses drop students off.
Buses from Morris County Tech were rerouted to Parsippany Hills High School, where students will spend the rest of the day or be transported to PHS for classes, Parsippany police said on Facebook.
The Denville incident troubled Joseph Pettorino, whose daughter is a student at Morris County Tech.
"All of these terror threat exercises have a cost," he said. "I only hope that the punishments are severe enough, and that problem elements are removed, not encouraged."
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