SOUTH WHITEHALL TWP., Pa. -

Students at a high school in Lehigh County were greeted by police at every entrance when they arrived for class Monday morning.

According to an email to Parkland High School parents from Principal Jame Moniz, a "non-specific threat" was directed towards a staff member that school officials found out about Sunday night.

Moniz said the person who made the threat was not in school Monday, and wasn't expected to be in school Monday, but as a precautionary measure, police and school officials limited entry points to the building to make sure this person didn't enter the building.

Police said this was specific to the high school only and was not a district-wide concern.

The incident is being investigated by South Whitehall Township Police.