A woman who witnessed a man's arrest in Melbourne's north could hold key information about what led up to his death.
Victoria Police on Tuesday issued a public appeal for help to find the woman after the death of a 24-year-old man at Craigieburn on February 15.
The man was assaulted twice that day; the first time, when he was confronted by two men after he appeared to try to break into a car on Hothlyn Drive in the suburb about 2.15pm.
He then got into a fight with a separate group of males on Mitford Crescent around the corner about 15 minutes later, police said.
Officers arrested the man after the second fight and while paramedics were treating him on-site, he became unresponsive and died.
Police arrested the two men involved in the first altercation - a 72-year-old and a 33-year-old from Craigieburn - but then released the pair pending further inquiries.
The investigation remains ongoing as police attempt to examine all of the man's movements on the afternoon of February 15.
On Tuesday, they released photos of a woman who they want to speak to as part of their investigation.
The woman - who had nothing to do with the fights - witnessed the man's arrest.
She appeared to stop and look straight at officers and the man as she walked by.
The dark-haired woman was wearing a bright blue and white patterned top, black pants, Birkenstock-style black slides and glasses.
Police are urging anyone who knows the woman to come forward.
