After British detectives sat in on interviews in Faro with witnesses last week, the Sunday Express can reveal Policia Judiciaria co-ordinator Ana Paula Rito is taking a broader look at leads which may not have been fully pursued.

She is now keen to learn more about the Brazilian couple, who are said to have expressed a strong desire to have a child when they were in the ­Algarve in May 2007 when Madeleine vanished.

A few days after Madeleine vanished from flat 5a of the Ocean Club in Praia da Luz, a British man came forward with his concerns about the couple and was interviewed by Portuguese detectives.

On the night of the abduction the man was closing his video rental shop just a few streets away from the apartment.

At 10.45pm, 45 minutes after Kate McCann had discovered that her daughter was missing, he noticed the Brazilian woman, aged about 25, driving past his shop in a red car.

He told police there was a dog in the front seat and the woman driver kept looking at something on the back seat which he could not see.

Her partner, a bald Brazilian man in his early 40s, had worked on a local farm but was fired after some machinery was damaged and later worked at Lagos marina, about four miles from Luz doing boat ­repair work.

The couple, who were staying on a yacht at the marina left shortly after the disappearance and have not been seen again.

A dark-haired woman seen hanging around the apartment at 8pm on the night Madeleine vanished has never been identified or traced.

On Friday expatriate British businessman Robert Murat was ­re-interviewed for several hours, the last of 10 witnesses to be seen.