Authorities said they received the phony call around 10:20 a.m., Oct. 26.
Officers and Lehigh County sheriff's deputies "conducted a systematic clearing" of the building and found "no threat to the public," APD said.
Police are investigating the source of the call and anyone with information is asked to submit a tip at 610-437-7721.
The incident comes just a month after a 15-year-old WAHS student was reportedly found in a bathroom with a loaded handgun.
At that time, district officials said they were considering installing metal detectors at school entrances as a security measure.
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