Police are appealing for public assistance after a man was assaulted in Geelong last month.
The incident occurred when the victim was assaulted by another man as he was waiting outside a La Trobe Terrace cafe just before midnight on 11 September.
Investigators believe the attacker had a hammer concealed in the sleeve of his hoody when he walked past the victim, a 20-year-old Norlane man.
After walking past the victim, the offender turned and struck the victim to the back of the head with the hammer.
The victim sustained a head injury and required hospitalisation.
Following the attack, the offender turned again to verbally confront the victim before walking south along La Trobe Terrace towards a nearby hotel.
Investigators have released an image of a man who they believe may be able to assist with their enquiries.
The offender is perceived to be Caucasian in appearance, with a medium build, red hair and had a triangle tattoo on his right hand.
At the time of the attack he was wearing cargo pants, a black hoody and black runners.
Anyone who witnessed the incident or with information is urged to contact Crime Stoppers on 1800 333 000 or file a confidential report at www.crimestoppersvic.com.au.