Homicide detectives are investigating the suspicious death of a 73-year-old woman found inside her Fitzroy North home in Melbourne’s inner north.

The woman’s son discovered her body in her bed just before 1am on Saturday morning after family members raised the alarm.

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While her cause of death is yet to be determined, detectives are treating the death as suspicious and have launched a full investigation.

Police are combing through neighbours’ security cameras and were particularly interested in footage showing the Vietnamese woman being picked up by a friend on Wednesday night, which could be one of the last times she was seen alive.

When she was found, neighbours said her back door had been left open.

“Well, that’s unusual because she always has the doors locked,” neighbour Janine Tims said. “So I think that’s why they might think it’s suspicious. And no one had heard from her for a couple of days.”

Neighbours have told 7NEWS the woman was unwell in recent days.

Police are now awaiting the results of an autopsy which will determine where the investigation heads.