The UK's national online child protection centre has issued an Internet video message aimed at anyone close to the person who was involved in the disappearance of Madeleine McCann.
Watch the video
The one-minute film includes fresh images of how Madeleine might look now, including one with dark brown hair and tanned skin in case she has been living in north Africa.
It is hoped that the message, which is supported by global law enforcement agencies, will be spread by the public via the internet.
Viral messaging on the Internet is now widely used in marketing and advertising but it is believed this is the first time it has been used to help solve a crime in this way.
The message is not aimed at whoever abducted Madeleine McCann but at a friend, neighbour, relative or colleague of that person.
The 60-second film urges them to reveal any secret they might have about what happened to Madeleine.
The film has been released in seven languages.
The police officer who heads the UK's Online Child Protection Centre, Jim Gamble, said he refuses to believe that Madeleine McCann is dead.
Mr Gamble said: 'The person we are looking to reach is likely to be a partner, family member, friend or colleague of the person or people who were involved in Madeleine's disappearance.'
