FORENSICS officers have begun probing an area of previously hidden ground during the search of scrubland close to where Madeleine McCann was last seen in Portugal seven years ago.
Two men in white overalls were seen entering a tent, which has been erected on a spot of interest to police in Praia da Luz on the Algarve.
The area, which was covered by undergrowth until yesterday, has already been subject to fingertip searches by officers in Metropolitan Police uniforms.
Two white gazebo-style tents were put up and connected together to hide the scene from the TV crews and press watching from the other side of the police cordon nearby.
They placed it on top of a spot where a piece of corrugated iron was discovered beneath undergrowth yesterday.
The section of metal, which is understood to have covered up a void in the ground, was then taken away by officers.
Local forestry workers have been clearing large areas of undergrowth within the scrubland to aid the search.
Another patch that was previously overgrown was earlier scanned with ground-penetrating radar equipment to probe for disturbed earth.
A man in plain clothes and without any police insignia wheeled the device along a section of ground.
The device uses radar pulses to take images of the subsurface of the ground to check for any anomalies.
It can be used to check for disturbances in a variety of substances, including rock, soil, ice and fresh water.
It can also detect voids and cracks in buildings and under pavements.
The developments came during a third day of investigations by British police and their Portuguese counterparts as they search for clues as to what happened to Madeleine, who vanished while on holiday in the resort in May 2007, aged three.
