Police have described a "revelation moment" in their investigation of the disappearance of Madeleine McCann, which changed their theory as to when the child may have been abducted.
They believe that "on one reading of the evidence" the abduction was planned beforehand.
However they are also investigating whether Madeleine was taken after she saw a burglar breaking into the room where she was sleeping.
Three-year-old Madeleine McCann disappeared in 2007 in Portugal.
BBC's Crimewatch program on Monday night showed the latest theories of investigating police as well as an appeal for help from Madeleine's parents.
The program featured a 25-minute reconstruction of the events leading up to Madeleine's disappearance.
After the appeal was broadcast, two callers into Crimewatch provided a name that matched the efit image.
Madeleine went missing on May 3 2007, on holiday with her family in the resort of Praia da Luz on Portugal's south-western tip.
The three-year-old disappeared from her family's holiday apartment.
The McCanns remembered the fun they had together by the resort pool, where they took the last photograph of Madeleine on the day she disappeared.
They put their tired children to bed in the ground floor apartment, and around 8.30pm went to a tapas restaurant 50m away, where they had dinner with friends.
Gerry McCann went to check on the children just after 9pm, and saw they were asleep and went back to dinner.
At 10pm Kate headed back to the apartment to check again.
She saw the children's door was wider open than it had been left. She looked into the room and realised Madeleine was not in her bed.
"She wasn't in our bed, and that was the first time that panic kicked in."
She noticed the window had been pushed open.
"I kind of knew straight away then that Madeleine had been taken," she said.
Detective Chief Inspector Andy Redwood, who is leading the investigation into Madeleine's disappearance, said police had made a breakthrough when they realised that a sighting at 9.15pm, previously though to be a suspect, was almost certainly just another man carrying his young daughter from the hotel crèche.
Previously this sighting had been the main focus of suspicion.
Eliminating this possibility allowed them to focus on other potentially significant sightings, later in the evening.
An Irish family told police they saw a man carrying a blond-haired child of three or four, possibly wearing pyjamas, away from the McCann's holiday apartment towards the beach around 10pm.
The witnesses said the man was white, 20 to 40 years old, of medium build, clean shaven and with short brown hair.
The child in his arms was not crying or in distress.
Earlier on Monday police released two 'e-fit' identikit pictures, constructed from descriptions of the man.
Redwood said it was not certain that this man had taken Madeleine.
"This man may or may not be the key to unlocking this investigation," he said. "Tracing and speaking to him is of vital importance to us."
There were many other lines of inquiry and other e-fits of other people were released as well, of people seen on the day of Madeleine's disappearance and the days leading up to it.
Police noticed that burglaries in the area had increased fourfold in early 2007 - and only three weeks before Madeleine's disappearance the same block of apartments was targeted, by a burglar who entered through the window.
Police are working on one theory that Madeleine may have interrupted a burglar.
However they also believe that the evidence suggests the abduction could have been pre-planned.
A blond-haired man was seen standing on a path near the apartment on the day Madeleine disappeared.
At 6pm that night another man was seen in the stairwell of the apartment.
Two men were seen on the balcony of an empty apartment, two doors away from the McCanns.
And around 11pm, two men were seen arguing with raised voices, but then when they saw they were being observed they walked away, talking in hushed tones.
The McCanns appealed to the public to come forward if they thought they could help.
"These cases can get solved," Mr McCann said. He said the 'e-fits' were their best chance of finding out what happened to their daughter
"Please have the courage to come forward ... and unlock this case," Mrs McCann said.
"It's not us that has committed this crime," she said. "It's the person who's gone into that apartment and taken a little girl away from her family."
They still desperately miss their daughter - especially on occasions such as her birthday.
"When it a special occasions and you should be your happiest, that's when it hits home," Mr McCann said.
He said the "ifs buts and maybes" eat away at you.
And Mrs McCann still regrets their decision to go to dinner that night.
The Portugese police investigation into Madeleine's disappearance was dropped in 2008, with all suspects cleared. British police opened their new investigation in July this year.
They are examining data from thousands of mobile phones used in the area near the resort before during and after Madeleine's disappearance.
They have also re-examined old documents.
- Fairfax Media