Casey Crime Investigation Unit detectives are investigating an arson in Hallam this morning.
It is understood unknown offenders smashed multiple windows of a vacant gym on Princes Highway about 1.45am.
A Molotov Cocktail was also thrown into the premises, causing damage to the entrance of the building.
At this stage, it is believed the offenders scene in a vehicle.
The investigation remains ongoing.
Anyone who witnessed the incident, has CCTV/dashcam footage or information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
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