Police have uncovered a new lead in the search for Madeleine McCann; a secret compound linked to the prime suspect in her disappearance.
Located in the southern Algarve region of Portugal – the same area where 3-year-old McCann vanished from a holiday apartment back in 2007 – the property belongs to convicted paedophile Christian Brueckner's ex-girlfriend Nicole Fehlinger.
News of the compound emerged after Fehlinger's father Dieter was recently interviewed for a second time by German authorities, who are reportedly taking the revelation "very seriously".
Dieter claims that his daughter and her former lover Breuckner, 44, were the only people who had access to the compound.
"No one knows that my daughter not only had the private residence in Portugal at her disposal, but also a separate compound," he told The Mirror. "No one has ever searched there or the property has never turned up in connection with Maddie."
At the time of McCann's disappearance, Fehlinger and Brueckner had been living together in a private residence very close to the secret compound.
Hidden by overgrown trees and weeds, the 5000sq m compound was guarded by four fierce Kangal dogs, which have the strongest bite of any canine in the world.
"The area is completely overgrown, not visible. No one could get in or out, only my daughter and perhaps [Brueckner] with her," Dieter said.
The former couple had regular phone conversations and even went for a weekend getaway in Lisbon together just months after Madeleine vanished, Portuguese court documents show.
Fehlinger, a mother of three, is not suspected of having any involvement in the disappearance of Madeleine.
Meanwhile, Brueckner has been convicted of other offences, including the rape of a 72-year-old American woman in Praia da Luz, Portugal, and remains in jail. He has denied any involvement in Madeleine's disappearance.
Brueckner broke his silence last month, penning a handwritten letter that slammed the Madeleine investigation as a "scandal".
A bizarre hand-drawn cartoon accompanied the letter, depicting two prosecutors ordering food at a restaurant, with one of the characters saying in speech bubbles: "I'll take the fillet forensics", to which the other replies: "Yummy, me too".
"Charging an accused is one thing," the letter reads.
"Something completely different – namely, it is an unbelievable scandal – when a public prosecutor starts a public campaign for prejudice before a court case is opened.
"Freedom of expression is not a basic right so that everyone can say and write what they want. Freedom of expression does not protect the majority.
"It protects the minority. It does not protect the most logical, most convincing or most popular views, but rather the outsider position."
It is believed the cartoon is a reference to investigators, who previously admitting they did not possess any forensic evidence linking Christian B to the case.