A former Scotland Yard detective believes he has come up with the five most plausible theories to explain the disappearance of Madeleine McCann.
Murder detective Colin Sutton said a trafficking gang could have snatched her to replace a dead child or she could have been snatched by a paedophile.
But he theorised the "most likely and credible scenario" for Maddie's disappearance was a targeted kidnap, reports Daily Mail.
Speaking to The Mirror, he questioned why traffickers didn't take one of Maddie's twin baby siblings instead - who would have no memory of their previous life and less physical identity.
As the 10th anniversary of Maddie's disappearance approaches next month, the investigator has analysed multiple theories for a new book.
Madeleine was just 3 went missing from Praia da Luz in Portugal in May 2007, almost a decade ago.
He said those closest to Maddie, including her parents, would have been the first line of inquiry for police.
But he added he believed Portuguese police appeared make this their only line of investigation early on in the probe.
He said: "By concentrating just on that scenario they may have missed tips or other lines that meant going down a completely different investigation route."
He said: "A trafficking ring is more likely than a lone paedophile or paedophile ring."
But unless the order was specifically for a young blonde girl, why her and not one of the twins?
"Has a young blonde girl died and their parents want to replace her? Or is there another reason for stealing to order?"
While cops initially believed Maddie could have wandered off and been killed, Sutton believes the tot would surely have taken her beloved toy "Cuddle Cat" if she had walked out of the apartment.
He said: "Incidents of children wandering off are much more common than a targeted or non-targeted abduction.
"However Cuddle Cat is a compelling fly in the ointment with this theory."
He said it was highly unlikely that an opportunist had snatched her, saying that most predatory paedophiles are "not interested in pre-school age children".
He said: "The chances of a predatory paedophile just happening across Madeleine and being able to abduct her without being detected are just so remote.
"I don't know of any other opportunistic abduction of a girl so young."
And he also believes it is extremely unlikely that she was killed as part of a burglary gone wrong, as most burglars are drug addicts looking for something small they can easily sell.
He said: "Junkies don't take 3-year-old girls."