Three New Jersey schools were evacuated Wednesday after bomb threats were phoned in for each location, but no suspicious devices were found and children were allowed back inside by midmorning.
Bomb-sniffing dogs and police responded to the three schools in Passaic; Roosevelt School on Harrison Street and Casimir Pulaski School on Fourth Street, both elementary schools, and Hope Academy, a high school serving special education students.
Students and teachers in all the schools were ushered outside and all schools in the district were placed on lockdown as a precaution while authorities swept the buildings.
Officials gave the "all clear" shortly after 10:30 a.m. and students were permitted to return to class.
Authorities believe the same person phoned in all three bomb threats, law enforcement sources tell NBC 4 New York. Passaic Mayor Alex Blanco called the threats "despicable" and said whoever made them "should be prosecuted to the fullest extent of the law."
Law enforcement sources say the police department has seen an increase in bomb threats across Passaic County in the week since the twin bombings at the finish line of the Boston Marathon killed three people and wounded more than 170 others.
The investigation is ongoing.