Detectives from Box Hill Divisional Crime Team are investigating following an armed robbery in Blackburn last week.
Investigators have been told the victim had arranged to meet a man at a Whitehorse Road service station to sell a Rolex watch about 9pm on Wednesday 9 October.
As he was talking to the first man, a second man struck the victim from behind with an unknown weapon while a third man punctured the tyres of the man's car with a knife.
A scuffle ensued and the victim was further assaulted.
All three unknown offenders ran from the scene after stealing the mans watch.
The victim, a 19-year-old Mount Waverley man received head injuries as a result of the incident and was taken to hospital.
Investigators have released CCTV of three men who they believe can assist with their enquiries.
Investigators are appealing for anyone with information to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
