A couple who died in a Melbourne fire had warned two men in the home of the growing danger, but failed to escape from the smoke and flames themselves.
The bodies of a man and woman, both aged in their 40s, were found in the burnt out remains of the unit in the city's west.
Police say the pair who died may have been in a relationship and the fire was too severe to save them.
The couple were also known to police and the house was previously the site of a siege.
Two other men, aged in their 30s, managed to escape from the Deer Park unit and were taken to hospital suffering from smoke inhalation and minor injuries.
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Neighbours awoke to screams and flames engulfing the property at 12.45am (AEST) on Friday.
Detective Acting Senior Sergeant Lionel Joseph says police have not yet pieced together why the couple who died weren't able to flee from the home.
"The deceased notified the two men about the fire and that assisted the occupants to get out," he told reporters at the scene.
"(But) we can't explain why the deceased didn't make it out."
He said the two men who escaped had been in the rear of the property and the dead couple had possibly gone back to bed.
A neighbour, Suzanna, 33, said she was startled awake by screaming and loud noises.
"When I woke up I thought it was fighting," she said.
"My husband was coming home and saw the whole thing. There was a loud bang and lots of smoke and flames coming out of the house.
"It's shocking. I wouldn't wish it on anyone."
Jake Lynch, who lives next to the unit, says he dodged flames himself to remove his car from the path of the fire.
"I heard screams, people yelling out `fire' from the front unit," Mr Lynch told Fairfax Radio.
"I went and woke my mum up. We called the fire brigade.
"We drove out the front driveway, past the flames coming out from the loungeroom."
Police say it's too early to say whether the two men in hospital were known to police as well.
The cause of the fire is yet to be determined and detectives from the arson and explosives squads are on scene.
