British police have released two images of a suspect in the disappearance of Madeleine McCann.
The efits are based on, they believe, descriptions of the same man and detectives have made tracking his whereabouts a priority.
The man was seen around the Praia da Luz resort in Portugal when Madeleine went missing on May 3, 2007.
Detective Chief Inspector Andy Redwood, who is leading a taskforce investigating the girl's disappearance, said: "The efits are clear and I would ask the public to look very carefully at them. If you know who this person is, please come forward.
"Whilst this man may or may not be the key to unlocking this investigation, tracing and speaking to him is of vital importance to us. We have witnesses placing him in the resort area around the time of Madeleine's disappearance."
The images were released ahead of an emotional new appeal Madeleine's parents, Kate and Gerry, will make on British TV.
The Sun newspaper reported that a holidaying Irish family saw the man at 10pm on the night of May 3 2008 carrying a child.
They said the girl was wearing pink or light-coloured pyjamas similar to the ones Madeleine was wearing, and that she was slumped against him.
Martin Smith, his wife Aoife and son Peter said they gave a description of the man to Portuguese police but no picture was ever released.
One of the McCanns' dinner companions on May 3 said she saw a man carrying a girl in pyjamas at 9.15pm.
Police say suspect is white, clean-shaven, medium height and build, with short brown hair and aged between 20 to 40.
The Daily Mail reported that Chief Inspector Redwood is set to announce "a revelation moment" in the investigation.
It also reported that police want to speak to two German-speaking men who were seen in Praia da Luz on the day of Madeleine's disappearance.
In the special appeal, the McCanns open up about the Madeleine-shaped hole in their lives. When asked how often they think about their daughter, who went missing when she was three years old in 2007, the couple say they feel the pain daily.
"When it's a special occasion, when you should be your happiest and Madeleine's not there, that's when it really hits home. Obviously, Madeleine's birthday goes without saying," Gerry McCann says.
His wife adds: "It's when you have big family occasions really. That's it isn't it? 'Family occasion' and you haven't got your complete family."
The BBC Crimewatch special, which airs on British screens on Monday evening UK time, also includes a new, 25-minute reconstruction of the events leading up to Madeleine's disappearance.
It follows a newspaper report that British police arrested a man after he boasted at a party of having recently seen Madeleine McCann on a Mediterranean island.
Britain's Sunday Mirror reported that a barrister had given a detailed statement to police after attending a party in Manchester where the man made the extraordinary claim.
The man boasted that he had been introduced to Madeleine on the island this summer. She was in the company of another adult.
The barrister said he took the claim seriously because of the level of detail.
The Sunday Mirror reported that the man making the claims was arrested during the week and computers were seized.
In a statement, Greater Manchester Police told the paper "a man was arrested ... on suspicion of possession of drugs and conspiracy to distribute indecent images of children".
He was bailed pending further inquiries.
Madeleine's disappearance is being investigated by Operation Grange.A spokesman from London's Metropolitan Police told Fairfax Media: "We are not providing a running commentary in relation to this."
If any arrest was made by Operation Grange it would be confirmed by the Met, he said.
Hopes of a new lead
Portuguese authorities closed their investigation in 2008, but the Metropolitan Police spent two years reviewing the evidence and opened their own probe in July this year.
Last week, the Met said analysis of mobile phone data from thousands of people who were at the resort of Praia da Luz when Madeleine disappeared could provide a new lead.
The detectives have interviewed 442 people in the past couple of years and have identified 41 potential suspects, although no arrests have been made.
"Primarily what we sought to do from the beginning is try and draw everything back to zero,'' Chief Inspector Redwood, said in a clip from the program released to the media. "Try and take everything back to the beginning and re-analyse and reassess everything, accepting nothing."
He said detectives were focused on the time between 8.30pm on May 3, 2007, when Kate and Gerry McCann left the apartment to dine at a nearby tapas restaurant with friends, to when Kate McCann found Madeleine was missing at 10pm.
"Our work to date has significantly changed the timeline and the accepted version of events that has been in the public domain to date,'' Inspector Redwood said.
The appeal will be shown in Germany and the Netherlands after Monday's British broadcast, in a bid to widen the search for new information.
Last week the McCanns said they were ''greatly encouraged by new information coming to light'' and that they hoped the BBC appeal would take them closer to finding Madeleine.
- Sydney Morning Herald