Portuguese police started searching an area of scrubland today, just nine miles from where Madeleine McCann was abducted.
Police vans, one carrying sniffer dogs, moved in at first light in the village of Arao, not far from Praia da Luz.
It is now 43 days since the four-year-old was taken from her bed as she slept in the Algarve resort.
A section of the police, known as GNR, cordoned off the road in the tiny village as they carried out their search.
Two days ago Portuguese police were told about an anonymous letter alleging that Madeleine had been buried under rocks in this area.
The information was sent to a Dutch newspaper, The Telegraaf, and claimed her body was just seven metres from the road.
Portuguese police started investigating the claim on Wednesday but it has taken until today to start any formal search proceedings.