Photo: vicpolicenews.com.au

Investigators believe a number of people were at an address on Foster Street, near Langhorne Street, on 2 November when a man was assaulted about 7am.

The victim, a 45-year-old Greenvale man, had an amount of cash stolen from him before the offender fled on foot.

The Greenvale man was located a short time later on nearby McCrea Street by a member of the public, who called 000 and alerted emergency services.

He was taken to hospital with a serious head injury.

Investigators have released still images and CCTV footage of a man they believe may be able to assist with their enquiries.

He is Caucasian and believed to be aged in his early 30s and unshaven with a medium build and light brown hair.

Anyone who is able to identify the man or has any other information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au.