YORK, Pa. — A Pennsylvania school district has closed schools for a third consecutive day as police continue to investigate threats made against students and staff.

The Central York School District cancelled classes for Friday following a series of threats on social media. Harrisburg schools and the Dauphin County Technical School also canceled classes on Friday due to similar threats circulating on social media.

Authorities have not provided specific details about the threats in each district, citing the ongoing investigations. Other schools in Pennsylvania have also received various threats via social media but have remained open.

The threats come in the wake of Valentine’s Day shooting at a Florida high school that killed 17 people.