Western Australian police have revealed why 4-year-old Cleo Smith, missing from a tent in a remote campsite at the weekend, could not have opened the zipper herself.
Speaking to reporters on Wednesday afternoon, Inspector Jon Munday said Cleo was too short to reach the zipper on her tent on her own on the morning she went missing.
Police said they are preparing for the worst after five days of searching for Cleo.
Cleo was staying in a tent with her family at the Blowholes Campground in Macleod, near Carnarvon, when she was reported missing about 6am on Saturday.
Munday said officers were bracing for the "nightmare scenario" that she might have been abducted.
But he remains hopeful that Cleo is still alive and says police will keep searching until they have answers.
Police have been working to two theories – that Cleo left the tent of her own volition and wandered off, or that someone took her.
Munday said police were still giving equal weight to the land search as well the investigation into a potential abduction.
"We will be here until we are satisfied that Cleo is not in this area.
"We have searched thoroughly all the high probability areas that Cleo could be in this campsite. We are now extending into the further areas where Cleo could have walked herself."
One of the zippered entrances to the tent was open when Cleo was discovered missing, Munday said, beyond a height she could have reached herself.
Her sleeping bag was also reported missing.
Munday said there if someone took her they would have had the opportunity to leave the campsite before police set up roadblocks around the area.
WA Police have said between 10 and 20 registered sex offenders are living in the area where Cleo disappeared.
Munday said police had identified and spoken to any registered sex offenders who were in the Carnarvon area.
He said police had no suspects in relation to the case.
Earlier on Wednesday, Deputy Police Commissioner Darryl Gaunt said officers had made inquiries into the registered sex offenders in the Carnarvon area but none of them were suspects.
"Part of the investigative strategies have included reaching them and making inquiries into their whereabouts and movements," he told 6PR radio on Wednesday.
"At this point in time, we're very comfortable with where we sit with those inquiries."
Gaunt said authorities remained hopeful of finding Cleo alive.
"While time is not on our side, there have been instances in the past where even small children lost in remote areas have still been found safe and well.
"There's been some rain — that gives us hope that there's water on the ground … we keep searching with every bit of energy that we have."
Gaunt said police were still first and foremost treating the case as a search and rescue mission, despite growing fears Cleo may have been abducted.
"From the moment this incident was reported to us, we launched parallel activities around a search and rescue operation, as well as an investigation phase.
"To say we're treating this as an abduction is not correct. We're treating it as a search and rescue mission, first and foremost, and that remains our mission."
Gaunt said police had received a lot of information from people who had been at the campground and reported hearing "certain noises" and seeing suspicious activity.
"We've investigated and responded to the vast majority of that. Most of them are explained."
Asked specifically about reports of a car heard screeching about 3am, he said: "We haven't ruled it out or in, it's a little bit unsubstantiated but we haven't ruled it out."
Gaunt agreed with the proposition that Cleo wandering off from the tent in the middle of the night with her sleeping bag did not seem to add up.
"No, it doesn't and look, it's every parent's worst nightmare, and I think all of our hearts go out to the family," he said.
"Their hands are tied as to what they can do.
"If I can give the comfort, the amount of effort that is going into this is second to none. We're not holding back any resources."
Gaunt said Cleo's father was interviewed in Mandurah, where he lives, but he was never a suspect in her disappearance.
"He was never ruled in as a person of interest, so he was interviewed predominantly for background and also to eliminate any possibility to confirm his movements.
"We're very comfortable of his movements that he was nowhere near the blowholes area."
Asked if police had questioned Cleo's mother and stepfather in the same way, Gaunt said no but there had been a lot of communication with them.
Gaunt urged anyone with information to come forward.
"We're getting information coming in from around the world and certainly interstate … the public response to this has been enormous," he said.
On Tuesday, Cleo's devastated mother Ellie Smith spoke publicly for the first time, describing the past few days as "horrendous".
"We're going to find her — we have to," Smith said.
She said Cleo would never wander off alone and would have asked for help to unzip her one-piece sleeping suit if she needed to use the toilet.
"She would never leave that tent alone."
Asked if they feared someone had taken Cleo, Smith said the family was still hoping to find her safe.
Smith said someone had to know where Cleo was.
"Someone has to — it's been four days."
The last time Smith saw her daughter was at 1.30am on Saturday when Cleo woke up to ask for water.
Cleo was sleeping beside her younger sister Isla who was in a cot, while Smith and her partner Jake Gliddon slept on a mattress in a room next to them.
Just a few hours later, Smith discovered Cleo was missing.
"She was gone. The tent was completely open. It was about 30cm from being open," Smith said.
Speaking about the ordeal through tears, an exhausted Smith revealed she had not been sleeping since Cleo vanished.
"Everyone asks us what do you need and really all we need is our little girl home," she said.
"We sit and watch the sand dunes and think she's going to run down it and back into our arms, but we're still waiting."
The search was hampered for several hours on Tuesday due to wild weather but was back on track by midday local time.
A GoFundMe page has been set up by local man Bill Kent to help Cleo's family and the search efforts, so far raising more than A$58,000.
Anyone with information was urged to call police on 131 444 in Australia.
Anyone who passed through the area between Friday and Sunday was also urged to come forward, especially if they had dashcam footage.