Police suspect a car was set alight shortly after being used to carry out a theft at Pakenham Golf Club in the early hours of Saturday morning.
A Toyota Land Cruiser with a tray had been driven to the golf club about 3.50am on Saturday 28 January to gain access to the grounds.
It is understood the vehicle was parked near the maintenance shed where the raiders stole about 100 litres of diesel fuel from petrol bowsers.
Shortly afterwards, police were called to the scene of a car fire at about 5.30am on Caldermeade Road in Lang Lang, where they found the same vehicle engulfed in flames.
On the same day firefighters were called to a peat fire at Lang Lang from 4pm near Samuel Lane, with the CFA issuing a smoke warning as they monitored the area over the weekend.
The fire was declared under control by 11am on Monday 30 January.
Police said that the second fire was not treated as suspicious.
