Cleo Smith: Police reveal why forensic officers were at family home for seven ...

Police officers scoured the family home of missing four-year-old girl Cleo Smith for seven hours as part of a 'routine practice' to eliminate all possibilities, Western Australia's top cop said. 

Forensic officers and detectives spent much of the day at the family's home in Carnarvon, 900km north of Perth, on Tuesday and left with two bags of evidence although it's unclear what was inside.

Acting WA Police Commissioner Col Blanch said the parents were not suspects in their daughter's disappearance and the search of their home was 'standard practice' into the investigation.

'We must do a thorough investigation,' Mr Blanch told 6PR. 

'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. 

'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.' 

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 the early hours of Saturday morning October 16 at the Blowholes campsite near Carnarvon.

Her heartbroken stepdad Jake Gliddon returned to the family home on Tuesday to allow police and detectives inside.

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. 

Although investigators had been to the home before, this was the first time they thoroughly searched inside with a forensics team.