Police are stepping up their patrols in Castletown after damage was caused to the cricket pavilion at King William’s College.
Between 4pm on Friday and 8am on Saturday 10 to 15 windows were broken.
Police say they think it was done by young people and have warned that someone could have been seriously hurt.
The school will now have to foot a significant bill to repair the damage.
Anyone with information about this incident can contact Castletown Police Station or Crimestoppers.