The discovery of human remains inside two burning cars in Sydney hours apart is just an eerie coincidence, police believe.
A body was found slumped in the driver's seat of a partially burnt-out Ford Fiesta in the city's west early on Tuesday morning, while a few hours earlier skeletal remains were uncovered in the rear of a Toyota RAV4 in the south.
Superintendent Craig Middleton acknowledged the cases were of similar circumstances but said police did not currently have any information to connect the two deaths.
"We're keeping a very open mind and we're exploring all the avenues," he said on Wednesday.
Emergency services found a vehicle alight at Waterfall in the Royal National Park south of Sydney shortly after midnight on Tuesday.
Firefighters extinguished the blaze before finding skeletal human remains inside the rear of the car.
The remains are yet to be formally identified and have been sent for forensic examination.
Supt Middleton said the vehicle was "well and truly ablaze" when emergency services were called to the scene, but the cause of the fire remained unknown.
"We simply don't know the circumstances behind that person's remains being found in that vehicle," he said.
Supt Middleton said officers did not suspect foul play and the death was not believed to be connected to organised crime.
Hours after the gruesome find in Sydney's south, police were called to North Parramatta to reports of a vehicle alight.
After extinguishing the blaze, firefighters found a body slumped in the driver's seat of a partially burnt-out hatchback.
Superintendent Barry Vincent said police were treating the death as suspicious and were following up reports of gunshots heard in the area about the time of the fire.
"We're certainly keen to speak to that person who may have heard gunshots," he said.
"There may have been a fuel source but what that is, I couldn't say definitively at the moment."
Neighbours said they heard what sounded like two or three shots ringing out shortly before police were called.
Another said she heard the sound of screeching tyres at the end of the street, believing the noise to be a getaway car.
"I heard there was like a 'pop pop' kind of sound, but I didn't think too much of it," Liza Bak told Nine News.
Police were seen scanning a nearby sporting field and bushland while detectives went door to door interviewing neighbours.
Two crime scenes have been established and forensic examination is under way to determine the identities of the victims.
Homicide detectives are investigating the Parramatta blaze and working to identify the remains.
Police are appealing for anyone with information or footage of the incidents to come forward.
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