Four teams of officers from the Portuguese Policia Judiciaria are involved in the operation, along with at least 20 of their German counterparts, Portuguese news outlet SIC said.
It has been reported that the prime suspect in Madeleine’s disappearance, convicted sex offender Christian Brueckner, 45, spent time in the area between 2000 and 2017. Investigators believe he killed Madeleine after abducting her from a holiday apartment.
Brueckner, who has denied involvement in Madeleine’s disappearance, was first identified as a suspect by German investigators. The Sun newspaper reported that the search was sparked after they discovered video and photos of Brueckner near the reservoir.
A no-fly zone has been put in place over the water and media and other onlookers are being kept a mile back from the site of the search.