A bomb threat was called in at John Witherspoon Middle School at 10:45 a.m. on Wednesday, according to a Princeton Police Department press release.
A computer-generated telephone threat was sent to the main office reporting a bomb in the building. Princeton police officers were put on alert and investigated the threat very soon after.
All of the students and faculty in the middle school were evacuated and redirected to a safe location. Students were allowed to return to the premises at 1:20 p.m., though police officers remained patrolling the school during the day.
There has since been a complete search of the middle school grounds by the New Jersey State Police and the Mercer County Sheriff Department, and they concluded that there was no explosive device.
Princeton High School and Riverside Elementary School received similar threats by telephone last week, but officials investigated these threats and labeled them as hoaxes. Allentown High School was evacuated due to a bomb threat on Thursday, NJ.com reported.