Police are appealing for public assistance after a man was located unconscious in Footscray on Saturday night.
Investigators have been told a passer-by found the man lying on the ground at the back of shops off Barkly Street about 5pm.
The man, who was identified as a 33-year-old from Niddrie, was transported to hospital where he now remains in a critical condition.
It is unclear how the man sustained his injuries at this stage.
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.