Police said a four-year-old Australian girl was found in a locked house in her hometown on Wednesday. Her disappearance shocked the country.

"My name is Cleo," the child said after the police broke into the house after an 18-day national search in the coastal town of Carnarvon in Western Australia.

Police said Cleo disappeared with a sleeping bag from a campsite in the outback of Australia on October 16 and has now been returned to her parents. The police arrested a 36-year-old man whose name has not yet been released.

"We are... looking for a needle in a haystack, and we found it," Col Blanch, Deputy Commissioner of the Western Australian Police, told Perth Radio 6PR. He added that the officials shed tears of gratification and joy over how their hopes were "achieved."

When she disappeared in the middle of the night, the family had been camping about 60 miles north of her home in Carnarvon. They woke up on October 17 and found that Cleo was missing not only in her tent, but also in the campsite.

The police initially searched the area around the camp, but after further investigation found that this was more likely to be a kidnapping incident. They said that Cleo was too short to pull the tent back to its original height.

The search caught the attention of Australians across the country as her family begged the public to provide any information about the whereabouts of their daughter.

Police Chief Chris Dawson said that four police officers broke into the house with a search warrant and found that Cleo's camcorder video made him burst into tears.

He will not elaborate on what the girl has experienced.

Dawson said she was "as good as you think."

Prime Minister Scott Morrison called this ordeal "every parent's worst nightmare."

He added: "The nightmare is over. Our most worried thing is not realized. This is just a huge relief, a very happy moment."

According to Reuters, the police team has 140 people working on the case, the public has provided more than 1,000 clues, and the state has provided a $1 million reward for the Cleo case.

Cleo's mother, Ellie Smith, recently posted on Instagram to celebrate her daughter's return, with the caption: "Our family is back again."