THIRTY-eight potential suspects have been identified for the abduction of Madeleine McCann, Scotland Yard said today as it launched a final push to uncover the mystery of the three-year-old's disappearance during a family holiday in the Algarve six years ago.
The potential suspects include 12 Britons believed to have been in Praia de Luz in 2007 when the youngster disappeared from the bedroom of her holiday villa.
The Metropolitan Police is set to apply to Portugal and three other unidentified European countries for information on individuals following a two-year trawl of thousands of documents collected during years of fruitless attempts to find the girl.
The step change in the inquiry comes after Home Secretary Theresa May responded to a plea for help from the family in 2011 and ordered a review of files compiled by police in Portugal and Britain and by seven firms of private investigators.
Scotland Yard has upgraded the review to a full investigation which allows them to apply to other countries for information on suspects and ask them to act on new witness evidence, leads and theories that they have identified during the review.
If any of the 12 Britons, some of whom live abroad, are eventually charged with an offence, they could potentially go on trial in this country.
Scotland Yard took the decision to launch a full investigation after the Portuguese authorities declined to re-open their inquiry shelved in 2008.
The unusual arrangement - which will see a small number of Metropolitan Police officers work alongside their Portuguese counterparts - is seen as the last realistic prospect of uncovering what happened to her.
A similar process was undertaken when British officers helped their Kenyan counterparts investigate the 1988 murder British woman Julie Ward in Kenya, but nobody has been convicted over her death.
Arrests are not imminent in the McCann case but the multi-million pound review by 37 officers is believed to have uncovered new theories about what happened to Madeleine on the night she went missing.
Scotland Yard declined to go into detail about what might have happened but said they believed the youngster may still be alive because of a lack of evidence to suggest otherwise. She would be aged ten if she was alive.
Madeleine was asleep in the family's holiday apartment as her parents dined at a tapas restaurant with friends nearby when she was taken.
Her parents, Kate and Gerry McCann, and their friends have been ruled out as suspects leading police to believe that she was snatched by a stranger.
After Portuguese police failed to find the girl, private investigators continued the work employed by the McCann family.
"We continue to believe that there is a possibility that Madeleine is alive.
The Government is funding Scotland Yard's review of the case, Operation Grange, and will continue to pay for the full inquiry.
Police have gone through nearly two-thirds of the papers in a laborious process of translation and logging more than 30,000 documents.
Some of the 38 that have been identified have not previously featured in inquiries into the girl's disappearance, which has been marked in the intervening years by sightings across Europe and wider afield and dogged campaigning by the young girl's parents.
The Portuguese authorities have stated that they will only open the inquiry in the event of a substantial breakthrough and it remains closed.
In a delicate diplomatic balancing act, Portuguese police will lead the latest inquiry but will be following up some of the 3,800 leads identified by the Met as part of the review.
The officer heading Operation Grange, Det Chief Insp. Andy Redwood, said: "We continue to believe that there is a possibility that Madeleine is alive.
"It is a positive step in our hunt for Madeleine that our understanding of the evidence has enabled us to shift from review to investigation.
"We have identified 38 persons of interest from a number of European countries. Twelve of those people are UK nationals who we believe were in Portugal at the time Madeleine disappeared."
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