A Cranbourne West man was assaulted in Rowville on the night of Friday 5 January after witnessing a petrol theft.
It is believed a white Kia sedan attended a service station on the Burwood Highway in Ferntree Gully shortly after 6pm.
The 31-year-old Cranbourne West man was exiting the petrol station when he witnessed the occupants of the Kia sedan drive off without paying for their fuel.
The man followed the Kia for a period through Ferntree Gully before driving off.
A short time later, he realised that he was being followed by the petrol thieves.
When he pulled up at a red light on Wellington Road, two people got out of the vehicle and began hitting him with bats and batons.
The pair then got back in their car and fled east on Wellington Road.
Members of the public who witnessed the incident were able to assist the man and contact emergency services.
The victim sustained a significant injury to his arm that will require surgery.
It is believed the same group may have been involved in other petrol drive-offs in the area between 11 November 2023 and 5 January 2024.
Investigators have released CCTV and images of two people they believe may be able to assist with their investigations.
The male is described as Caucasian in appearance, aged in his early 20s, of a thin build with brown hair. He was seen wearing a grey hoodie, dark green shirt, and black shorts.
The female is described as Caucasian in appearance, aged in her 20s, of a solid build, with dyed red hair. She was seen wearing grey shorts and a black crop top.
Any witnesses, anyone with vision or information is urged to contact Crime Stoppers on 1800 333 000 or www.crimestoppersvic.com.au