On Wednesday, more than 30 Portuguese and German police extended their search of the headland at the reservoir, as heavy-duty brush-cutting equipment was brought in to strip out shrubs and clear a large swathe for searches.
The search was expected to move into its third day as the Portuguese source insisted German officers had drawn up a detailed map of key locations, some still untouched. The source added that the site could be linked to other crimes the prolific sex offender has committed.
Meanwhile in Germany, Christian Wolters, the Braunschweig prosecutor, stressed that the searches were not based on any confession, but very strong “indications” that the site was of significance.
In an interview with NDR, the German public service broadcaster, he said: “We have indications that we could find evidence there. I don’t want to say what that is exactly, and I also don’t want to say where these indications came from.
“The only thing that I would clarify is that it doesn’t come from the suspect. So, we don’t have a confession or anything similar now, or an indication from the suspect of where it would make sense to search.
“It was other indications that prompted us to conduct the search.”
His comments underlined how the German authorities were taking seriously the informant’s claims that Brueckner had gone to the reservoir shortly after Madeleine’s disappearance.
While it is not known who the source is, former friends of the German national have previously played a key role in telling police of his alleged crimes.
Two of his friends told detectives that they had found a videotape at the farmhouse where he lived on the outskirts of Praia da Luz showing a rape and two other sex attacks. The tape has not been recovered.
Brueckner, who has denied any involvement in Madeleine’s disappearance, was identified as a murder suspect in June 2020. He has a long history of crimes, including petty theft and drug trafficking to the sexual abuse of children.
In 2019, he was convicted in Germany of the sadistic rape of a 72-year-old American tourist after breaking into her villa half a mile from the McCanns’ holiday apartment in 2006. He is currently serving a seven-year prison sentence and is due for release in three years’ time.
Scotland Yard and German police claimed that Brueckner’s mobile telephone received a 30-minute call close to the McCanns’ holiday apartment an hour before Madeleine disappeared.
On Wednesday, officers used powerful strimmers and a heavy-duty brush cutter to remove shrubs before the area was raked and pored over by sniffer dogs.
Some items, including items of clothing, were believed to have been bagged and removed by officers.
However, none have been identified as potentially linking to the missing girl.
Emergency services and officials from Portugal, Germany and the UK have been seen holding briefings near blue police tents at the scene.
It was believed that German police have found numerous pictures Brueckner took of himself at the waterside at Barragem do Arade.
It was also believed that the images were found on a USB stick and laptop both seized from a derelict factory he owns in Germany.
