'A monumental error.' How police found 4-year-old Cleo Smith.

It was just after 6am on the morning of October 16, 2021, when Ellie Smith called triple zero. 

"Hi, umm, my daughter’s gone missing," the mum-of-two told the operator.

"How old’s your daughter, love?" he asked over the phone. 

"She's four," Smith replied, as her voice broke. 

"Have we checked everywhere?" the operator continued. 

"Yeah, we have done two laps of the place and we grew up here, so we've kind of looked everywhere," she responded. 

That morning, Smith woke up to find her four-year-old daughter, Cleo, was missing from her family's tent while camping at a remote campsite in Western Australia. 

For Smith and her partner, Jake Gliddon, it didn't take long to realise Cleo must have been taken. 

"The second we realised she was gone and her sleeping bag was gone, that was the second we knew she did not walk away. There was no drag marks of the sleeping bag, we knew she couldn't have carried it," Smith told 60 Minutes on Sunday.

"It was just a nightmare... deep down we knew she did not walk away, she was taken."

Within seven minutes of the phone call, police made their way to the Quobba Blowholes campsite to find out what happened. 

In bodycam footage aired by Channel Nine, Smith is seen answering police questions and describing how they found the family's tent. 

"The zipper [of the tent] was open and it was open basically like three quarters of the way," she told an officer. "She's quite small and little, I don't see her opening it the whole way."

The moment Cleo Smith’s mum realised her four-year-old had gone missing from their tent, she rang triple-0. This never before seen vision captures Ellie Smith’s anguish, and marks the start of the extraordinary job ahead for police to find Cleo.

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Earlier that morning, Terence Kelly, who lived in the nearby town of Carnarvon, drove to the campsite, before taking Cleo from the family's tent and making his way back home. 

Back at the camp, police acted urgently and a land, sea and air search quickly got underway, with 60 SES volunteers forming the frontline. 

"The first two officers who responded to that call for a missing child, within four minutes of [their] arrival... had established a crime scene," WA Police Minister Paul Papalia told 60 Minutes. 

But as the search continued and hours turned into days, Cleo was nowhere to be found. 

Five days in, the SES search was called off, leaving police to continue the investigation into the four-year-old's disappearance.

Working around the clock, officers obtained CCTV footage and searched rubbish bins for any potential evidence. 

"There was massive amount of data and analysed," said Papalia. "There were tens of thousands of hours of CCTV imagery from service stations, from private houses, from small businesses within a thousand kilometre radius."

Recalling the investigation to 60 Minutes host Tara Brown, Smith said police told her Kelly "was on drugs" and "was coming to steal from cars or shacks" when he unzipped the tent and took Cleo. 

"He had his fantasies and he was trying to make them come to life. He wanted a daughter [and] he wanted a wife."

From there, he reportedly drove him via a dirt track home and turned his phone off so "no-one knew he was there". 

But as Brown explained, Kelly made "a monumental error" that ultimately led him to being identified as a suspect.

During his journey back home, he reportedly turned his phone back on around 3.05am, registering a ping to a nearby mobile phone tower. 

"[The tower] recorded thousands of phones, hundreds of thousands of data sets and in that, captured one bit of information that led to the investigation of Kelley as the suspect," said Papalia. 

"It was ultimately that start of that thread of the investigation." 

From there, police worked to sort through data and remove the "hundreds of thousands of leads that were wrong". 

Detectives amassed information from government agencies, Kelly's social media use and phone data. 

Eventually what had started as a "wide spectrum of investigation" narrowed and the focus turned to Kelly.

On Tuesday November 2, officers watched Kelly leave his house in his car and later pulled him over just before midnight. 

They later discovered Cleo inside the locked house, minutes from her family home, 18 days after she had gone missing. 

In footage watched around the country, an officer holds Cleo as Detective Senior Sergeant Cameron Blaine tells her, "We’re going to take you to see your mummy and daddy," 

“We’re going to take you to see your mummy and daddy.”

This is the moment Cleo Smith was rescued by Western Australia Police, 18 days after the four-year-old went missing.

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Looking back, Smith said "there was no way" she thought someone from Carnarvon took her daughter. 

Kelly later pleaded guilty in January 2022 to the single charge of abducting Cleo. He was sentenced 13 years and six months in jail. 

Since the rescue, Smith said Cleo still has nightmares about what happened every week.

"She still has her sad nights, her nightmare nights," she explained. "Some things she just can't explain."

Gliddon added that they try to give her hugs and reassure her she's ok. 

"[We] give her cuddles, reassure her that everything is fine, sneak her a few a chocolates," he said. 

Last week, Kelly lodged an appeal against his sentence, with his lawyer arguing "appropriate weight" wasn't given "to the applicant's childhood disadvantage and trauma". 

Feature Image: 60Minutes/Channel Nine.