Limestone Coast Police are appealing for witnesses to an incident of property damage, that saw Mount Gambier High School flood.
A fire hydrant at the high school was deliberately turned on earlier this week, and was left running until a member of the public turned it off almost six hours later.
The event caused flooding to the school oval and car park.
Officers now calling for witnesses to the incident to come forward.
Locals with information that may assist in the investigation are being urged to call Crime Stoppers on 1800 333 000 with the option to remain anonymous.