Homicide Squad detectives are investigating a fatal assault in Box Hill last night.
Emergency services were called to reports of an assault in the foyer of a Young Street apartment building about 7.45pm.
Responding officers attended and arrested a 42-year-old Box Hill man at the scene.
He was taken to hospital where he remains under police guard.
Two victims were located, with one sustaining a minor facial injury that didn't require hospital treatment.
After speaking with witnesses, officers became aware of reports that a third person had been assaulted.
A search of the building was conducted and a man was located deceased in a stairwell.
At this early stage in the investigation, detectives believe parties were known to each other.
Investigators are working to determine the circumstances surrounding the incident and the investigation is ongoing.
Any witnesses, anyone with CCTV/dashcam footage or information is urged to contact Crime Stoppers on 1800 333 000 or confidentially at www.crimestoppersvic.com.au
