Cleo Smith search and rescue final two hours revealed as mobile data played ...

Detectives used mobile data to track down the alleged abductor of Cleo Smith as the final two hours of the search and rescue for the four-year-old are revealed. 

Sources close to the investigation claim the mobile phone data was crucial in helping police to identify Terence Darrell Kelly, 36, as a prime suspect. 

'His phone was allegedly in the area as part of the data collection,' a source told The West Australian. 'That is part of the information that led the taskforce to him.'

There are at least three new mobile base stations located not far from the remote campsite where Cleo vanished from at Quobba Point, in Western Australia, on October 16.

Telecommunication providers then gave police a list of phone numbers that had been used in the area during the times of interest. 

Detective superintendent Rod Wilde said the data was then layered with other information before Kelly became a person of interest.

'So we put the phone data over numberplate-recognition data, CCTV, witness accounts, forensics... And when you layer them on top of each other you solve crimes and that is merely what we have done here.'

Police tailed Kelly in an unmarked police car at 11.24pm on Tuesday - just hours before they raided his housing commission home at Carnarvon at 1am on Wednesday. 

Detective senior sergeant Cameron Blaine said officers had been waiting for Kelly to 'go mobile and leave the premises'.

'It was clear in my head what had to occur so it was: 'OK, let's do that'.' 

Dashcam footage from a passing taxi captured the moment Kelly was pulled over by the unmarked police vehicle as he drove down Robinson Street.

A second unmarked police vehicle pulls up in front of the parked car to prevent any chance of escape.

A bystander recalled watching police then pin Kelly to the ground before arresting him.

'We saw one of the detectives on top of the guy pinning him down on the curb ... you know really vigorously,' they said.

With their prime suspect now in handcuffs, detectives made the decision to search his housing commission home at 12.46am on Wednesday.  

Detectives then found Cleo playing with toys in one of the rooms which had been locked.

'I just saw a little girl sitting there and didn't think about anything else than picking her up,' Detective senior constable Kurt Ford said. 

It will be a day WA Police Commissioner Chris Dawson will never forget as he recalled new details of the rescue to the state's 7,200 officers in internal weekly publication From The Line.

'It was a day that will go down in history as one of the greatest triumphs for WA Police Force. For many officers, it will be the greatest day of their careers,' Commissioner Dawson said.

'My heart has been bursting with pride since I first received a phone call from Deputy Commissioner Col Blanch advising of Cleo's rescue shortly before 1am.

'Today, I want that pride to fill the hearts of all employees of this great agency.'

The commissioner met Cleo along with her mum Ellie Smith, stepfather Jake Gliddon and her grandparents at the family home just hours after the little girl was rescued.

'As Cleo and her mum were exchanging kisses and hugs she fell asleep in Ellie's arms,' he recalled.

'None of us will forget that day. It's why we join the police force.

'From the bottom of my heart - which is so very swollen with pride - thank you to all... Enjoy this moment in history and let it carry you forward in service of our community.' 

He also sent an photo of Cleo smiling and waving in hospital to WA Premier Mark McGowan, who described the little girl as well adjusted, sweet and delightful during his visit to the family home on Thursday.

Commissioner Dawson also recalled the heart-melting moment he first heard the audio of the little girl's rescue and the first words she uttered, telling officers: 'My name is Cleo'.

'In policing, we frequently see the worst of society and the circumstances surrounding Cleo's abduction certainly fit that bill,' he said.

'But on occasion...we also have the great privilege of having a front row seat to witness the very best of humanity and the rescue of Cleo is one of those moments.

'It should be treasured.' 

Meanwhile, Cleo's parents are under strict instructions by police not to discuss the four-year-old's 18-day nightmare with her. 

Detective Senior Sergeant Cameron Blaine revealed on Thursday that discussing the details of what happened could jeopardise the prosecution's case by diluting the accuracy of her information.

Terence Darrell Kelly, 36, who is not known to the family but lives just minutes away, was charged with multiple offences on Thursday night, including Cleo's kidnapping.  

He appeared in Carnarvon Magistrate's Court on Thursday afternoon, where he was formally refused bail.

Police have warned Cleo's parents to wait until specialist child abuse detectives formally interview the four-year-old before talking about the traumatic events with her.

'This is still a matter that needs to go before the courts, there's certain aspects of what we saw that is going to be evidence, and I don't want to say anything that's going to prejudice that,' Senior Sergeant Blaine, who was one of the four detectives that rescued Cleo from the locked house said.

'It's not always the case that people understand that, but we want to see a successful prosecution at the end of the day for the people who are responsible.

'We've given them advice around that, and that must be incredibly hard for them, so we appreciate their assistance and cooperation with that.'

He said the family have been 'cooperative and understanding' all the way through the hellish ordeal as police worked tirelessly to track down Cleo's alleged abductor.

'They understand where we are going with the investigation and what remains to be done,' Senior Sergeant Blaine said.

'Our family liaison officer is going back out there now to speak to them and talk them through the next steps.'

A heart-warming audio clip of the moment detectives first found Cleo alone in a room playing with toys was heard for the first time on Thursday. 

Sergeant Blaine can be heard asking the little girl 'what is your name?' three times before she finally falteringly replied: 'M-my name is Cleo.'

He said police have tried to share as much information they can with the parents but at this stage investigators are still piecing all the details together themselves. 

'We share with them what information we can. They know what they need to know,' Senior Sergeant Blaine said.

'Obviously it's still a time where we're exploring all the facts. We're getting information from, still, a number of different sources. Some of that information is completely wrong.

'So we're careful about what information we share with people, we want to make sure we're 100 per cent sure of the facts.' 

It's been 45 hours since police dragged Kelly out of his car at about midnight on Wednesday and slapped handcuffs on him. 

The process of charging has been delayed after Kelly was allegedly attacked by another prisoner inside a police holding cell within hours of his arrest.

He was taken to hospital with head injuries and released after medical treatment.

But police revealed on Thursday he had been returned to hospital for a second time after he is understood to have suffered new injuries while alone in his police cell.