A smouldering tow truck caught the eye of PSOs in Springvale.
They reported the fire in Newcomen Road about 10.20pm on Friday 26 January.
CFA crews attended and extinguished the flames.
The cause of the fire is unknown but police are treating it as suspicious and forensically examining the truck.
Greater Dandenong CIU urged anyone with information to call Crime Stoppers on 1800 333 000.
