WINDSOR -- School board officials say a Windsor Catholic school was evacuated as a “precaution” while Windsor police investigate a situation.

Police were called to St. John Vianney Catholic Elementary School at 8405 Cedarview St around 8:20 a.m. Wednesday.

Staff and students were allowed to return by mid-morning.

Windsor Essex Catholic District School Board spokesperson Stephen Fields says as a precaution they moved all of the students and staff to the church across the street.

They only allowed students back into the building when police assessed the situation and determined that it is safe to enter the building.

“Children are being supervised at the church and are safe there,” Fields said during the evacuation.

He said there is no need for parents to pick up their children, but some parents opted to anyways.

Police say they are investigating an unsubstantiated threat.