Missing four-year-old girl Cleo Smith has been found safe and well in a locked house in Carnarvon, WA police say.
Cleo Smith after her rescue. Photo: Western Australian Police
A 36-year-old man with "no family connection" has been taken into custody and is being questioned by detectives.
Cleo's mother Ellie Smith has expressed relief in an Instagram post, saying: "Our family is whole again."
According to a statement from Deputy Commissioner Col Blanch, police broke into the house about 1am and found her in one of the rooms.
One of the officers picked her up and asked her, 'What's your name?"
She replied: "My name is Cleo."
She has been reunited with her parents.
WA police said a Carnarvon man had been taken into custody and was being questioned by detectives.
Cleo had been missing since 16 October, having disappeared from the tent she was sleeping in with her parents at the Blowholes, a popular camping site north of Carnarvon.
Her disappearance sparked a widespread search across Western Australia.
"This is the outcome we all hoped and prayed for," Deputy Commissioner Blanch said.
"It's the outcome we've achieved because of some incredible police work and I want to thank Cleo's parents, the West Australian community and all of the volunteers.
"And of course, I want to thank my colleagues in the Western Australian Police Force."
Prime Minister Scott Morrison expressed relief at the news,
WA Police Commissioner Dawson said he had seen the vision of police going into the home, and that Cleo was "smiling" and "as well as we could expect in the circumstances".
He said the man in custody had no link to Cleo's family."But there was some information we followed up on. We've been following a lot of forensic leads, and it led us to a particular house.
"We're still questioning the fellow, so it's difficult for me to expand on it too much more."
Dawson said it was a "wonderful day for this little girl and her loving family".
"It is a really special day for Western Australia. Indeed, I know the nation is rejoicing over the fact that we have been able to conduct this operation and we never gave up hope.
"I know that Cleo's parents never gave up hope, and it is just a such a wonderful opportunity for me to say, thank you."
WA's Minister for Police Paul Papalia said Cleo's rescue "wasn't the result of a sighting, or a suspicious event - it was the result of hard police grind".
A neighbour of the house where Cleo was found said the man who lived there was "quiet" and said he noticed the man buying nappies from a local supermarket recently.
"We didn't click who … he was buying them for," he said.
Dawson said finding Cleo was a "wonderful result".
"To find a vulnerable little girl after 18 days … obviously people think the worst, but hope was never lost. Australia's rejoicing."
Deputy Commissioner Blanch said police had been "looking for that needle in a haystack".
"Late last night they found that needle that led them to that address and rescued Cleo," he told Channel 7's Sunrise program.
He said detectives "broke down with relief" after finding Cleo in the house.
- ABC