Scotland Yard has urged Portuguese authorities to reopen the search for Madeleine McCann as detectives said there are 195 potential leads to finding her alive.
The detective leading the Metropolitan Police review said the case can still be solved before officers released a picture of what she might now look like as a nine-year-old.
Detective Chief Inspector Andy Redwood said he believes her disappearance was a stranger abduction, as he said there are 195 "investigative opportunities".
Police refused to say what evidence they had uncovered to suggest Madeleine is alive.
Mr Redwood confirmed that his team of more than 30 officers involved in the case had been out to Portugal seven times, including a visit to the family's holiday flat in Praia da Luz.
It will be five years ago next week since the three-year-old went missing as her parents, Kate and Gerry McCann, dined with friends nearby. A spokesman for the McCanns said the family was pleased with the image.
Mr Redwood said his 37 officers had dealt with 40,000 pieces of information but the "primacy still sits in Portugal" in the attempt to find her.
Commander Simon Foy said: "Most significantly, the message we want to bring to you is that, on the evidence, there is a possibility that she is alive and we desperately need your help today to appeal directly to the public for information to support our investigation."
Mr Redwood said "evidence that she is alive stems from the forensic view of the timeline" that there was the opportunity for her to be taken. Investigations show "there do appear to be gaps", he added.
Detectives in Portugal are also understood to want the case reopened but must gain judicial approval via the courts.