Secret network of caves: Ex-police chief's latest Madeleine McCann theory

A former Portuguese police chief believes Madeleine McCann was snatched and taken to a secret network of caves under the resort where she was last seen alive.

Paulo Pereira Cristovao, who became the head of Portugal's missing children agency the year the 3-year-old vanished, put himself in the shoes of the kidnapper to come up with the theory and lambasted his ex-colleagues for their mistakes.

He said the errors are to blame for the fact there are no answers in the complex case a decade after Maddie's disappearance from Praia da Luz, the Daily Mail reported.

With the 10th anniversary of the incident just days away, Cristovao said he emulated what a person new to the area would have done in the situation.

"Where would I put the body of a girl?" he told the Sunday Mirror.

"I stood at the apartment door; to the right is the town of Portimao. There are lots of people there, lots of buildings.

"If I had kidnapped her that's not the way I'd want to go. I would want to go left, and find the first side road. I put my car on that road, and I went straight to Burgau. It's a nearby beach, with a lot of rocks with caves.

"It's a good place to put somebody. As far as I know the police never went there, because you would need divers."

He dismissed a number of outlandish theories such as an alien abduction and called the speculation of Maddie's parents Kate and Gerry's involvement "bull****".

"We've heard theories so stupid over these 10 years. When we don't understand something, we complicate it."

Cristovao reserved some criticism for his former colleagues and thinks somebody is still concealing evidence.

"I think this case has lots of mistakes: from many persons, from many situations, from the police and maybe from the government," he told the Mirror.

"At the end of the day we all forgot one person: Madeleine McCann."

With more theories emerging as the anniversary nears, an investigative journalist believes the then-3-year-old was snatched from the street after she wandered outside to find her parents.

The Sun's Danny Collins speculated the shutters of the apartment in the Algarve could not be prized apart as has been previously suggested, and could only be opened from the inside.