On April 28, at 10:04 a.m., the Riverside Elementary School received a pre-recorded message that was general in nature and threatened to harm children. The school notified Princeton Police headquarters and patrol units responded to Riverside School and found the school to be safe. As a precaution, police remained at the school throughout the day. Patrols have been increased in the areas of all the schools throughout the municipality. All Princeton private and public schools were notified of the incident by the police department. Each school took actions deemed appropriate, including sheltering the children inside. The Princeton Police Department will continue to investigate the origin of the threat.