A disturbing letter has been sent to a Dutch newspaper detailing the supposed location of the body of missing four-year-old Madeleine McCann.

|PIC1|In response to the letter, Portuguese police started a search Wednesday of an area of deserted scrubland just 13 miles to the north of where the young British girl was snatched from.

Police chief inspector Olegario de Sousa said he was investigating the matter but declined to give further details. "We are following up this information," he said.

An anonymous letter sent to the Netherlands' biggest selling newspaper, De Telegraaf, has been passed on to authorities in Portugal. The letter told that Madeleine's "body" could be found "under branches or stones" 15 km (9 miles) from where she disappeared.

Two sheets of paper were sent with the letter, showing a map of an area of the Algarve, 15 km (nine miles) from the spot where Madeleine, who disappeared at the beginning of May, was last seen.

The map showed a cross and two question marks saying "possible place where Madeleine could be found".

Already the letter and map have been identified as being similar to one sent to the same newspaper in 2006 revealing the location of two missing Belgian girls who were found after De Telegraaf received a tip-off.

Kate and Gerry McCann's young daughter was kidnapped more than 40 days ago and the parents recently expressed their desire to step back from the media spotlight as the search for Madeleine continues.

Madeleine vanished 3 May after her parents left her and her siblings sleeping in their holiday apartment while they went to a nearby tapas bar inside their hotel complex.

Over the six weeks since Madeleine's disappearance, Kate and Gerry McCann have led a huge publicity campaign to find their daughter. In addition, they have embarked on a spiritual journey to hold onto their Catholic faith, regularly attending a local Catholic church as well as recently travelling to Rome to meet Pope Benedict XVI, who prayed for the missing girl.