(Radio Iowa) – Classes are canceled district-wide in Waterloo today (Wednesday) over safety concerns. Someone made a threat on social media Tuesday night, threatening to blow up four school buildings. The threat posted to Facebook, targeted East and West High Schools, George Washington Carver Academy and Central Middle School. Snap shots of the threat were shared multiple times on social media.

In a statement released early today, district officials said police and school staff worked throughout the night to investigate the threat as they try to identify the person or persons responsible for the post. District officials say while great progress was made in resolving the issue, more of the investigation needs to be completed before students can safely return to school.