On Wednesday, Scotland Yard released an updated photo of what they believe the little girl would look like today.

Madeleine was four when she went missing during a family vacation in Portugal on May 3, 2007. She has never been located.

Police in London said they've uncovered evidence during a year-long review that leads them to believe the young girl is still alive.

They hope the new evidence will encourage Portuguese authorities to reopen the case, which has been closed since 2008.

Police are also hoping to speak with anyone who was at the resort of Praia da Luz between April 28 and May 3, 2007.

"From the outset we have approached this review with a completely open mind, placing Madeleine McCann at the heart of everything we do. We are working on the basis of two possibilities here. One is that Madeleine is still alive; and the second that she is sadly dead," detective chief inspector Andy Redwood said in a statement.

"Based on the former we are releasing the age progression image today with a specific appeal," he said. "If you know where Madeleine McCann is now or you have new direct information/evidence about what has happened to her then please contact us."

Madeleine's parents, Kate and Gerry McCann, were initially suspects in her disappearance, but were cleared of any involvement.

Since then, there have been some sightings of the young girl, including last July when a British tourist thought she spotted Madeleine in India, and earlier this month when someone reported spotting her in Nerja, located on the southern coast of Spain, 520 km south of Madrid.

The new photo of Madeleine is posted on FindMadeleine.com, which was set up by her parents.

"It's never too late to do the right thing," a message on the website says, urging anyone with information to come forward.

If alive, Madeleine will turn nine on May 12.