Forensic police who spent three days searching the family home of missing little girl Cleo Smith would have been looking for 'signs of injuries or struggles', a top criminologist said.
Detectives spent four hours on Tuesday scouring the property in Carnarvon in north-west Western Australia as they probed the four-year-old's disappearance from the nearby Blowholes campsite in the early hours of October 16.
Police then searched Cleo's family home for a third time on Wednesday as part of 'routine practices' to eliminate all possibilities.
Her mother Ellie Smith and step-father Jake Gliddon have been ruled out as potential suspects in the ongoing police investigation as it enters its thirteenth day.
Ellie Smith pictured with her daughter Cleo. The four-year-old vanished from the Blowholes campsite near Carnarvon in north-west Western Australia in the early hours of October 16
Police desperately searching for Cleo Smith (pictured) have searched the campsite the little girl went missing from, as well as her home, to gather more evidence as the AFP joins the hunt
Crime scene expert Dr Xanthe Mallett though said it was important for police to look for 'potential issues' at the home before ruling it out as a line of inquiry.
'They may be looking for signs of injuries or struggles, just to rule out any kind of potential issues that may have happened at home,' the University of Newcastle criminologist told Sunrise.
'You would have to look at the family, that would be part of the investigation sadly.
'They need to make sure that they collect the evidence that may be available at the beginning so it is not lost so I'd certainly expect them to search that family property as part of any routine investigation.'
The expert said 13 days was a 'really long time' for a young child to be missing.
'Obviously she could be anywhere in the country had she been abducted,' Dr Mallett said.
Forensic detectives spent much of Tuesday scouring Cleo's family home in Carnarvon and emerged with two evidence bags
'It is a significant worry and every day that passes, obviously getting more concerned for her safety.'
Crime scene expert Dr Xanthe Mallett said officers searching the home would have been looking for signs any kind of struggle had occurred
Officers involved in search efforts have since turned their attention back to the Blowholes campsite amid police fears the four-year-old girl was abducted and taken elsewhere.
Police from Taskforce Rodia are understood to have taken ash samples from several burnt-out campfires near shacks along the beachfront on Wednesday.
About 100 officers are on the ground searching for Cleo and the Australian Federal Police have joined the suspected abduction case to boost search efforts with advanced technology, intelligence and forensics abilities.
Home Affairs Minister Karen Andrews confirmed the AFP's involvement in the hunt for little Cleo in Parliament on Wednesday.
'Australians can be certain that we will continue to equip our law enforcement and intelligence agencies with the tools and the resources that they need to combat this very serious crime - and especially crimes against children,' Ms Andrews said.
It's understood police from Taskforce Rodia took ash samples from several burnt-out campfires near shacks along the beachfront
Civilian investigators have been sending locals messages over social media with one man chartering a helicopter to search an area hundreds of kilometres from the town, the West Australian reports.
However when approached by the publication, the man denied he was a bounty hunter and was instead surveying for 'oil' and 'gas' deposits.
Acting WA Police Commissioner Col Blanch said the search of the family home was 'standard practice' and did not indicate they were suspects in Cleo's disappearance.
'The parents have been nothing but helpful. We've worked very closely with them, they've let us into their home, they've let us into their cars, their phones, everything,' Mr Blanch told 6PR.
Police scoured Cleo's family home for the third time on Wednesday as part of 'routine practices' to eliminate all possibilities (pictured, the family)
Little Cleo Smith and her step father Jake Gliddon, who has 'raised her as his own' are pictured together
The heartbroken step father of Cleo (pictured in a green singlet and sunglasses) earlier returned to the family's home for the first time since his little girl vanished from Blowholes campsite in Western Australia 11 days ago
'That is a normal part of an investigation and we must follow it thoroughly.
'Our job is to eliminate everyone that was at that campsite, and that is a systematic and thorough approach in doing so in any investigation. And that really is the focus of the investigation at the moment.'
Officers are also looking into CCTV of a car that was seen driving down a highway near the Blowholes campsite in the time window Cleo disappeared in.
The footage was taken from a home on the North West Coastal Highway, which reportedly shows a sedan travelling down the road at about 3am.
A distressed mother revealed her daughter was approached by 'a man in his late 40s with a beard driving a small red car' while they were camping at the popular holiday spot
Two people on their way to work had earlier told police they saw a car turning south off Blowholes Road at about 3am on the day Cleo vanished.
Police are now working to identify the driver and registration plates to determine whether the car seen in the footage is the same one in the reports, 7News reports.
Meanwhile, the attempted abduction of a child several years ago at the Blowholes campsite heightened fears a kidnapper could be operating in the region.
A newly resurfaced social media post reveals a girl was approached by 'a man in his late 40s with a beard driving a small red car' at the popular holiday spot in 2014.
The girl's distressed mother lodged a complaint with police at the time, warning the man asked her daughter to 'go for a drive in his car' but she refused and ran back to her family.
In the attempted abduction from 2014, the little girl wasn't able to provide a thorough description of the man's appearance, and it appears nothing ever came of the police report.
Detectives are now looking into footage taken from a home on the North West Coastal Highway, near the Blowholes campsite, which reportedly shows a sedan travelling down the road at about 3am
But she shared the post publicly hoping to warn other parents who might bring their children to the area, adding it would be a 'good time to remind our precious ones of stranger danger'.
There are now concerns within the local community that Cleo's disappearance could be linked to the incident.
Since the post was initially unearthed, several people have reported it to Crime Stoppers, hopeful any potential links will be thoroughly investigated.
Mr Blanch said while they were keeping 'open minded' about Cleo's disappearance, the 'highest probability' was that she had been abducted.
The four-year-old hasn't been seen since early on Saturday morning, October 16 at the Blowholes campsite near Carnarvon.
Cleo was last seen at 1:30am by her parents alongside her mother Ellie, stepfather and baby sister Isla (right) on their first camping trip together when s
The four-year-old girl's teary-eyed mother Ellie Smith told a TV interview on Monday that the couple had hardly been back to the house, finding it too agonising to return without their daughter.
The little girl in pink pyjamas was sleeping in a tent alongside her mother Ellie, stepfather and baby sister Isla on their first camping trip together.
She was last seen by her parents at 1.30am on October 16 when she woke up to ask for a drink of water.
But by 6.30am when her parents woke up, little Cleo along with her red and grey sleeping bag had vanished.
Cleo's heartbroken mother asked the question on the entire nation's lips in a desperate plea for answers she posted to social media last week
A massive land, sea and air search has continued for almost two weeks but there is still no signs of the pre-schooler and detectives have no firm suspects.
To flush out information the WA government last week announced a $1million reward for any information that can lead to Cleo's whereabouts.
Immense scrutiny has followed Ms Smith and her partner Mr Gliddon since their nightmare ordeal began, with hoards of online sleuths and 'amateur detectives' pointing the finger at them.
The devastated couple vehemently on Monday night denied any involvement in Cleo's disappearance and made a heartfelt plea to bring her home.