School officials at Lodi High School in Bergen County made an announcement over the school loudspeaker that someone might be armed inside the building. Police swept the school, going door-to-door and clearing students in each classroom. All students were patted down before they were released.
Nearby Hasbrouck Heights School District also locked down its schools in response to the warning.
The lockdowns were lifted at 11:30 a.m., about an hour after they were put in place.
Officials are understandably wary after Central Connecticut State University was locked down Monday when a man wearing a costume appeared to be carrying a gun. A man terrorized shoppers inside Westfield Garden State Plaza mall Monday night, firing several shots and later committing suicide.