The detective leading a review of evidence related to Madeleine McCann's disappearance is confident the case can be solved.
DCI Andy Redwood said Scotland Yard had the "best opportunity" to solve the mystery because it was the first time information from all sources had been considered.
His team of 28 detectives and seven civilian staff were sifting through around 40,000 pieces of information and "seeking to bring closure to the case".
Madeleine was nearly four-years-old when she went missing from her family's holiday flat in Praia da Luz in Portugal on May 3, 2007 as her parents Kate and Gerry McCann dined with friends nearby.
The official investigation was shelved in July 2008 but Scotland Yard's review of the case, Operation Grange, was launched last year when David Cameron responded to a plea from Madeleine's parents.
DCI Redwood said his team was analysing "every single piece of paper" generated in the investigation.
"Anything is possible and clearly, within that material, the answer could lie," he said.
The team is drawing together information from Portuguese law enforcement bodies, British police and private investigations commissioned by the McCanns.
Asked why he believed the operation was unique, DCI Redwood told the BBC's Panorama: "Because at no time before have those three elements been drawn together in one place."
While Portuguese police remain the lead agency in the case, and it would be up to them to decide whether to reopen it, he said his team in London aimed to solve the mystery.
The review "will give us the best opportunity... to bring them the best-quality information to assist them in making that decision".
Operation Grange has so far cost the taxpayer £2million (NZ$3,977,550).
- DAILY MAIL