Homicide Squad detectives are investigating the circumstances surrounding the death of a male in Wyndham Vale overnight.
Police were called to reports of a group of youths fighting in a park on Haines Drive, near Ribblesdale Avenue, about 11.30pm on Thursday, 10 January.
One male, who is yet to be formally identified, was located with a stab wound.
He received medical treatment but died at the scene.
Two other males were taken to hospital with non-life-threatening injuries.
Four males were arrested nearby and are assisting police with their enquiries.
Police have cordoned off the area and a crime scene is in place.
Anyone who witnessed the incident or has dashcam/CCTV footage, or any information is urged to contact Crime Stoppers on 1800 333 000 or visit www.crimestoppersvic.com.au