School officials say it was around 8:45 a.m. Thursday that the threat was found in the form of graffiti in a bathroom.
The nature of the threat led to an immediate lockdown and evacuation.
School officials say all students and staff are safe.
By Noon the school said the building had been searched and deemed safe for re-entry.
Anyone with information about the threat is asked to contact the Medford Township Police Detectives at 609-654-7375 or the confidential police tip line at 609-714-0302.