MENOMONIE, Wis. (AP) — All public schools in Menomonie are closed because of a shooting threat.

The written threat was left in a Menomonie High School bathroom days ago. District administrator Joe Zydowsky says the message threatened there would be a school shooting on Wednesday. Zydowsky says since investigators haven’t yet found the person or people responsible, it’s better to take precautions.

READ MORE: MN Skateboarder Completes Journey Across New Zealand To Combat Human Trafficking In His Native Vietnam

All school-sponsored activities are also canceled Wednesday.

READ MORE: Large Tech Conference, VeeCon, Underway In Minneapolis

Classes are to resume Thursday.

MORE NEWS: Man Fatally Shot On Downtown St. Paul LRT Platform; 2 Others Killed In Separate Shootings

(© Copyright 2015 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)