PINE TWP, Allegheny County — Pine-Richland Middle and High schools will be open Thursday in a state of heightened security following a “specific cyber threat” against the schools.

Both the Northern Regional Police Department and the FBI Joint Terrorism Task Force are investigating the threat that shut down the schools Wednesday and canceled all after-school activities. All elementary schools were open Wednesday.

On Thursday, students will not be permitted to wear backpacks or “other bags” and will be subject to a general search upon entering the building, according to an online letter from Superintendent Brian Miller. Books, lunches and other supplies must be carried in a clear plastic bag.

Police involvement at the schools included K-9 units securing the schools and the stadium, and having officers staffed at both buildings for the remainder of the day and overnight. A phone call to the Northern Regional Police Department was not returned Wednesday.

The middle school was the target of another threat Tuesday, which also caused increased security measures. The district did not say whether the threats were related.

Middle school teacher Patty Cekella, who lives in Harmony, said despite the threats she feels the district is making its best efforts to ensure safety.

“They want to portray a safe environment for both the teachers and the students, so they’re doing the things they need to do to make everybody feel safe in a professional manner,” Cekella said.

The district encouraged anyone with information related to the threat to contact its tip line at 724-449-8477.