A mother critically injured in a suspicious fire that left her young daughters in hospital is not yet well enough to speak to investigators trying to piece together what happened.
A gas cylinder exploded inside their family home in Chadstone, in Melbourne's east, on Wednesday night, injuring the woman, 37, and girls eight and 10.
The girls are in a stable condition at the Royal Children's Hospital while their mother is fighting for life in the Alfred Hospital.
A Victoria Police spokesperson said the woman was not in a position to speak with detectives, who are keen to discuss the fire with her.
A 36-year-old man who lives at the townhouse, but was not there at the time, has spoken to police and been ruled out as a suspect.
Dozens of firefighters battled the blaze, with flames burning through the roof of the two-story townhouse.
Fire crews found the woman and two girls unconscious in an upstairs bedroom and carried them from the smoke-filled home, which Fire Rescue Victoria Commander Paul Eckholdt described as a "difficult rescue".
"They were carried out and taken out to the front where Ambulance Victoria paramedics and firefighters were waiting," Cmdr Eckholdt told ABC Radio.
"They did have some burns and they also had some airway burns as well."
The fire destroyed bedrooms, an ensuite and caused a partial structure collapse while the rest of the home received smoke and water damage.
Investigators are also probing a fatal fire at a home in Langwarrin in Melbourne's south east.
Emergency services were called to a blaze just after 2am on Friday at the residence on Lyppards Road.
Three people inside escaped but another person, who is yet to be formally identified, was found dead inside a bungalow at the back of the property.
The cause of the fire is not yet known.
