Police officers from Scotland Yard have attended a "secret" meeting in Lisbon with their Portuguese and German counterparts to work out where Madeleine McCann could be buried, reports claim.
The forces met to pore over the details of suspect Christian Brückner's life in the Algarve at around the time when Madeleine went missing, with reports suggesting German police may travel to Praia da Luz for "one last roll of the dice" in their investigation.
According to the Portuguese daily Correio da Manha, the meeting took place "recently" at the Lisbon HQ of the Policia Judiciaria.
"Wells and ditches have been looked at with a fine-tooth comb, but no signs of the remains of the missing girl have been found," the Portuguese officers are said to have told British police.
The abandoned wells are a 15-minute drive from Brückner's rented cottage on the outskirts of Praia de Luz, on a narrow road leading down to a beach where the he used to park his VW camper van.
While the Metropolitan Police are still treating Madeleine's disappearance 13 years ago as a missing persons inquiry, German police are calling it a murder investigation.
Both forces are continuing to try to gather information on Brückner, a convicted paedophile and rapist who is currently in a jail in Germany on drugs charges.
"They regard it as essential to work out his routine in 2007, when Madeleine disappeared and Brückner was living near the Ocean Club where she vanished from," Correio da Manha said.
The report that German police want to return to Praia da Luz followed German prosecutor Hans Christian Wolters' admission that, without new clues, the 43-year-old Brückner will never be charged over Madeleine's disappearance.
His lawyers insist he is innocent. The Metropolitan Police were contacted for comment.