The Waterloo School District announced Sunday that all of its school buildings will be closed Monday due to vandalism discovered inside Waterloo Junior High School over the weekend.

Students throughout the district were to return to classes Monday from Easter break.

In a communication to district parents, Waterloo Superintendent of Schools Brian Charron said that vandalism was sustained early Saturday morning at WJHS.

“Individuals emptied a fire extinguisher into the building, causing significant clean-up necessary on both the first and second floor of the building,” Charron said.

The notification added that school officials consulted with an environmental company, local health department and the Waterloo Fire Department, “who all agreed that air quality testing should be completed prior to students and employees returning to the building.”

Charron said that due to logistical issues with closing one school building rather than all buildings, the district declared Monday as an “emergency day” with the hope that classes can resume in full on Tuesday.

The Waterloo Police Department said it is investigating the incident.

Check for more on this incident as more details become known.