Three people believed to be a mother, father and son have been killed in a shocking house fire that turned the sky orange as it ripped through a granny flat in southwestern Sydney and threatened a neighbouring unit block on Wednesday night.

Three bodies were found in the wreckage of the granny flat at the rear of the home on Cornelia St, Wiley Park.

Police said a family of three – a 52-year-old man, a 43-year-old woman and a 16-year-old boy – lived in the granny flat.

Fire in South West Sydney kills family of three

Fire crews were called to the home about 9.45pm. They were able to extinguish the blaze, but it caused extensive damage to the property.

Investigators are yet to formally identify the three people or determine the fire’s cause.

One resident who lives close to the home said he heard “crackling” about 9.30pm, just before they were about to go to bed.

“We heard some crackling outside and we just thought it was some kids or something playing outside, but we opened the balcony and went out to have a look and the sky was orange,” he said.

“There was a huge plume of smoke, we could see the roof of the granny flat was on fire and we immediately ran outside to see if we can assist, but the fire had already taken hold and it was a very scary moment.”

The neighbour said at one point the flames were close to a huge tree in the backyard, and he was wondering if it was also going to catch fire.

NSW Fire and Rescue Commissioner Jeremy Fewtrell said firefighters encountered a “well developed” blaze as they arrived on scene.

“There were flames coming out of the property at the rear of this block, so (firefighters) then had to make access through the side of the property and through the garden, which was quite challenging,” he said.

A neighbour named Doreen said her husband helped evacuate an elderly woman living in the home at the front of the property.

“My husband ran out and started banging on the door to get the old lady out and called out to the family living out the back,” she said.

“We got her out, but the fire was too far gone to even get anywhere near the back house. My husband tried but it was too far gone.”

“It’s very tragic. Very sad. They were nice people.”

Mr Fewtrell said a fire in the backyard had to be extinguished before officers could begin putting out the flames coming out of the building.

“In the process of that, very tragically they have located three bodies inside the property … unfortunately the people weren’t able to be successfully rescued,” he said.

“We take this opportunity to remind people of the seriousness of fires at any time, but particularly in the depths of winter. While we’re having these cold spells we do always see these house fires and we remind people of the importance of having working smoke alarms.

“Fire investigators have worked through the night with NSW Police forensics officers to examine the scene and the process of determining the fire cause and origin is still underway.”

Campsie Police Area commander Sheridan Waldau said the granny flat had been “fully engulfed in flames” when police arrived on scene shortly after the first fire crews.

“Campsie police assisted with the evacuation of a neighbouring premises, and once the fire was extinguished, the search of the premises located the bodies of three persons inside. They are yet to be formally identified,” she said.

“Campsie detectives are working alongside state crime arson squad and fire investigators to assist in establishing the circumstances around the fire … we know that a family resides within the granny flat. We’re working with extended family members at the moment to try and establish identification.”

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