A mother-of-seven has been sedated after detectives told her three of her children were killed in a house fire that was allegedly lit by their father.
Dean Heasman, 28, allegedly barricaded his partner Stacey Gammage, 29, and their kids inside their government-owned home in Lalor Park, in Sydney's west, at about 1am on Sunday and set it on fire.
Two boys, age three and six, were taken to Westmead Hospital in a critical condition but died of their injuries.
Once firefighters extinguished the flames, they found the body of a 10-month-old girl. Her body was removed from the property during forensic investigations on Sunday afternoon.
Detectives swarmed the home throughout Sunday looking for clues as to how the blaze began, and whether Heasman allegedly used a fire accelerant.
Among the evidence removed from the house were two water bottles with a brownish petrol-like liquid inside.
Police allege Heasman held the front door shut when emergency services arrived and shouted, 'Let me die here' as the children screamed for help inside.
Heasman is reported to have suffered burns to his skin and throat and the affects of smoke inhalation during the tragedy and is now in an induced coma as detectives wait to interview him.
Dean Heasman, 28, and Stacey Gammage, 29, are pictured together. They had seven children, three are now dead
Pictured: A forensic investigator pulled a bottle of brownish petrol-like liquid from the scene where three kids burned to death
Pictured: Forensics holding a second bottle of tea-brown liquid, during an investigation into the cause of the blaze
Neighbours told Daily Mail Australia that all three front rooms of the home were quickly engulfed with flames, before power lines began to spark and snapped off the house.
Local resident Jarrod Hawkins, whose daughter was friends with one of the surviving children, was hailed a hero after rushing to the burning home and saving a nine-year-old girl and her three brothers, aged 4, 7 and 11.
The eldest boy told his rescuers: 'Dad tried to kill me.'
Once Mr Hawkins left the burning home with four children, they were placed on the other side of the road before another neighbour Damien Dubois decided to move them away from the scene.
'I had the four kids and they were cold so we picked them up and took them into the back room of my place,' Mr Dubois told Daily Mail Australia.
'I was trying to console them. The two younger kids weren't saying anything so I picked them up and took them out of the way of all this trauma.
'They didn't need to watch it all.'
Mr Dubois recalled Heasman taking some of the children on quad bike rides around the local neighbourhood just a few weeks ago.
The government-owned property in Lalor Park was quicky engulfed in flames in the early hours of Sunday morning
Pictured: A fire and rescue worker shovelling soot and debris from the property on Sunday
Neighbours and family friends left floral tributes for the three kids who died on Sunday
Family friends arrived at the scene after news of the tragedy broke on Sunday, with many leaving floral tributes.
One family friend, Douglas King, added: 'I wouldn't have believed it if I didn't see it with my own eyes.
'[Heasman] was always with his kids and he was good to the kids - nice, calm and collected. He was telling me last year he had a newborn on its way.'
Mr King said he was shattered by the tragedy because he thought Heasman, who he affectionately called 'Deano reamo' and 'Deano the albino' was a 'respectful person with morals'.
He added: 'Deano was a good person. It’s mad. It's devastating. I hope the kids fight through it. I hope they survive. I feel bad for Stacey.'
Another said: 'I've known Deano since we were grasshoppers in pre-school and I can't believe this.'
Neighbour Jarrod Hawkins (pictured hugging his son) was praised for rushing into the burning home. Police said his actions 'saved further lives from being lost'
Neighbour Damien Dubois (pictured) rushed to the scene to bring the surviving children inside, away from the burning house
During a press conference on Sunday, Blacktown Police Acting Superintendent Jason Pietruszka said Mr Hawkins' actions at the scene 'saved further lives from being lost'.
He was unable to confirm whether Heasman was armed while trying to stop others from entering the property, but he said that would be a line of inquiry within the coming days.
Homicide Squad Detective Superintendent Danny Doherty said police were treating the fire as a domestic-related multiple homicide.
He said at Ms Gammage and her surviving children are being treated at Westmead Hospital for burns and smoke inhalation.
Heasman is under police guard in an induced coma in the intensive care unit. No charges have been laid.
'At this stage it does appear the 28-year-old is responsible for multiple deaths of young lives that have been tragically taken away,' Det Supt Doherty said.
'We're alleging the 28-year-old man took actions to prevent the young people inside being rescued.'