Police in Western Australia have revealed it is “very unlikely” a third party was involved after a mother and two children were found in a burnt-out car in Perth.

The body of a woman in her 40s, a 10-year-old girl and an eight-year-old boy were found in the back seat of a car at John Graham Reserve in Coogee, west of the city, on Monday morning. They are believed to be from the same family.

Emergency services were called just after 12 pm yesterday and it has been reported that a red hatchback was on fire. Police haven’t completely ruled out another person could be involved, but said it was “very, very unlikely there is a third party involved”.

Major Crime Division Detective-Inspector Quentin Flatman told reporters it appeared one of the parties inside the car had started the fire. He said investigators were “certainly looking at” the possibility the incident was a murder-homicide.

The father of the children had left for a trip to the US Sunday evening and is now on his way back to Australia following the tragedy.

“His reaction was what we would all expect in the circumstances. He is currently on an aircraft coming home so he can look for answers himself,” Det-Insp Flatman said.

He added the relationship between the woman and the father was normal, happy and healthy.

“The father is in shock,” he said.

“If this couldn’t get any worse, that poor man will have to be on a plane alone.”

Det-Insp Flatman said emergency services only realised there were bodies in the car after firefighters had extinguished the blaze. Police initially confirmed at least one body was found in the vehicle, with the scene now the subject of a major homicide investigation. The car was towed to a police forensic holding yard Monday evening with the bodies inside.

More than a dozen officers worked throughout the night to determine to begin to understand how the tragedy unfolded. Det-Insp Flatman said the mother and children were last seen about 11 am on Monday in Canning Vale.

Witnesses have reported hearing what sounded like gunshots before the fire began, with police saying they do not know yet whether the fire was the sole cause of death.

Det-Insp Flatman said gun-like sounds were consistent with noises typically made by burning cars.

“We suspect, which we will confirm during our enquiries, that the popping or the gunshot sounds that were heard was the fire consuming the motor vehcile itself,” he said.

The trio lived in a home south of Perth, near Coogee. Det-Insp Flatman added police were committed to leaving “no stone unturned” in the wake of the tragedy, which he said was all the more upsetting given it concerned children.

At the current stage of the investigation, officers had yet to determine why the incident occurred.

Extended family members who offered assistance to police had been “pivotal” in early parts of the investigiation, Det-Insp Flatman said.

Detective Senior Sergeant Cameron Blaine, who led the rescue effort for Cleo Smith, is among those investigating the incident.

“I’m very shocked,” another man told  7News.

Image: 9News