An Irish couple could hold key evidence in a fresh investigation launched into the disappearance of British child Madeleine McCann.
A two-year review of the case documents by British detectives has been upgraded to a full investigation into the youngster's unexplained disappearance.
It has identified 38 "people of interest" from a number of European countries, including 12 from the UK.
Evidence provided at the time by members of the Smith family, from Maple Drive, Drogheda, Co Louth, was considered credible by the review officers.
Martin Smith and his wife Mary revealed to investigators how they saw a man carrying a young child through the streets of Praia da Luz in Portugal on the night Madeleine went missing.
She disappeared on May 3, 2007, from her family's apartment on the Algarve.
The Smith family told police how they had left Kelly's Bar in the resort at around 10pm
They then passed a man walking down the middle of the street who was carrying a girl aged about three to four years old.
It was claimed that the child's head was lying against the man's left shoulder and her arms were hanging down alongside her body.
Madeleine was almost four when she was reported missing by parents Gerry and Kate McCann.
The Smiths returned home the day after the incident and it was only after they had seen the media reports of Madeleine's disappearance that they noted the encounter's significance. They later travelled back to Portugal to give police a statement.
So far, the review team has examined more than 30,000 documents generating almost 4,000 fresh lines of inquiry, but still have one-third of the information to examine.