Portuguese police today started investigating an area just nine miles from where Madeleine McCann was abducted after a tip off from a Dutch source.
An anonymous letter claiming the four-year-old lies buried under rocks in deserted scrubland was sent to newspaper De Telegraafand passed on to the Portuguese Policia Judiciaria.
It was thought to pinpoint an area north of Odiaxere, north east of Praia da Luz from where the girl was snatched 41 days ago.
Chief Inspector Olegario Sousa said the information was being taken seriously and "everything necessary" was being done to validate the allegation.
"There have been exchanges between Dutch police and us ... We are checking the information like we check everything in this case for importance," Chief Insp Sousa said.
Asked if the search involved digging, he said: "If the information gives us a precise location where we can look, we will do it."
According to De Telegraaf, the letter said Madeleine was buried "north of the road under branches and rocks, around six to seven metres off the road" in a barren and deserted landscape. A map came with the letter, with crosses marked on it.
The information is being taken seriously because it is thought to be similar to a letter sent to the same newspaper last year, giving details of the rough location of the bodies of two missing Belgian girls.
Stacey Lemmens (7) and her step-sister, Nathalie Mahy (10) disappeared while playing outside in Liege on June 10 last year.
Their bodies were found on June 29th, a day after De Telegraafreceived two maps marked with crosses and handwritten text. Today, a source at the newspaper said it had received two anonymous paragraphs of similar handwritten text written in Dutch.
"We received an anonymous letter with a map in it marked with the spots where Madeleine was buried.
"The police in Holland are taking it very seriously because it looks like the same sender as one we received one year ago in another case of missing children.
"The letter said the girl should be found six to seven metres from a road. We have been there but haven't seen anything but the area is so wide that you should be there with 100 searchers."
It is understood the Dutch newspaper did not publish the letter but passed it on to police authorities. Details of the letter have also been posted on the Find Madeleine website.