A woman and a six-year-old girl have died following a stabbing in Mill Park on Thursday night.
Emergency services were called to Kellaway Crescent about 7.50pm following reports of a stabbing.
On arrival, officers found a man, woman and girl with critical injuries, police said.
The woman, 39, died at the scene.
The girl was taken to hospital in a critical condition, where she later died.
The man was taken to hospital under police guard in a critical condition, police said.
It is believed all parties were known to each other.
Anyone who witnessed the incident or with footage or further information should contact Crime Stoppers.
Details: 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au