This morning between 7:30 and 7:45, a paraprofessional reported to work and entered their classroom on the west side of Liberty Valley Intermediate School. They noticed broken glass on the floor. Upon further inspection they noticed a hole in the double pane glass windows. The para immediately went to the office to notify principal Lee Gump. His inspection found a mark in a door across the room and a spent bullet laying on the classroom floor. The hole in the window indicated it was a bullet hole. Mr. Gump notified district police officer Matt Hunter and the Superintendent. Additionally, as students and staff were now arriving at the building, all persons were kept inside and away from exterior doors and windows.
At that point, we did not know the time of the incident but had reason to believe it occurred after Saturday afternoon. At that point in time, we did not know if there was an external threat. The building was locked down and persons were kept away from windows and doors. The PA State Police were called as was the other school police officer Larue Brion. The State Police arrived and investigated, including performing an exterior sweep to ensure there was no external threat. Additionally, school buses were alerted to be available to dismiss students but were staged off site.
Once the PA State Police gave feedback that they felt there was no external threat (roughly 9:45AM), and out of an abundance of caution, we decided to dismiss students at 10:15. This communication went out at approximately 9:45AM. We wanted to give some advanced notice, but did not want parents coming for pick-up to be on campus prior to getting State Police OK that the perimeter was clear.
The State Police brought in an evidence team. They continue to investigate as does the School District police force.
–Harry Mathias, Acting Superintendent
Original source can be found here.

