Officials say the sound that was thought to be gunfire at Valley Forge Military Academy in Wayne, Pennsylvania, was actually popping bubble wrap.
A student who lives in The Village, at the Eastern University rental apartments located on the Valley Forge Military Academy and College property, heard what was thought to be a gunshot and called 911.
The school was placed on lockdown for approximately an hour beginning at around 6pm on Monday.
Police arrived on the campus with guns drawn, but soon realised there were no signs of an active shooter or shooting.
Cabrini University along with Eastern University were placed on lockdown due to the incident.
Eastern University alerted all on their St. Davids campus to remain indoors. Around 10 minutes later, they said the lockdown was lifted.