Homicide Squad detectives are investigating a woman's death in Frankston.
Emergency services were called to a home in Daly Street, Frankston, about 5am last Saturday.
They found a 45-year-old woman in a critical condition.
Ambulance Victoria spokesman John Mullen said the woman was in cardiac arrest.
She was taken to Frankston Hospital, where she died on Tuesday.
Police say the exact circumstances leading to the woman's death are yet to be determined.
Anyone with information should call Crime Stoppers on 1800 333 000.