According to Detective Chief Inspector Andy Redwood, who's heading a team of 35 officers, after combing through nearly 100,000 pages of evidence, they hope to persuade Portuguese authorities to reopen the case.
Redwood says they are about one quarter of the way through and, so far, have discovered, "some other very promising lines of inquiry – which is very good for the future."
"On the evidence we have reviewed to date," he said in a statement, "we believe there is a possibility that she is alive."
Meanwhile, just days before the fifth anniversary of Madeleine's disappearance while on a family vacation in Portugal, British police have released a computer-generated image of what she would look like as she approaches her ninth birthday, which falls on May 12.
Urging members of the public to look at the age progression image, Redwood hopes people will come forward "if you know where Madeleine McCann is now or you have new direct information [or] evidence about what has happened to her."
British police also want to hear from anyone who was in the resort of Praia da Luz between April 28 – May 3, 2007 who have not already spoken to police in Portugal or the U.K.