Police working on a new search for missing Madeleine McCann are hunting for a camera containing images of the toddler and two other victims.
Investigators believe the camera could hold key evidence on victims involving the same man.
Portuguese police have now concluded a three day search of the Arade reservoir and surrounding area after German investigators received a 'tip' and requested a search.
The area is around 30 miles from where three-year-old Madeleine disappeared in Praia da Luz in 2007, the Mirror reports.
Convicted German rapist Christian Brückner is currently the number one suspect in her alleged murder and the reservoir is said to be his favourite spot.
German prosecutors received "certain tips" about Brückner which led to the three day search.
Now fresh information suggests officers were looking for a camera that may contain key photographic evidence.
Items taken from Brückner's home during a 2007 raid were thrown into the reservoir, a criminal informer told German prosecutors.
While Brückner was in jail, two key witnesses Manfred Seyferth and Helge Busching broke into his home.
They told German investigators a video camera and gun were discovered at the isolated Floral home, just a few miles from the reservoir.
The pair have claimed that footage on the camera showed Brückner torturing and raping an American woman and a girl aged about 15.
Brückner claims a drug deal went wrong and now the men are trying to set him up.
Investigators are said to have found video and photos of Brückner at the reservoir. He has reportedly denied any involvement in Madeleine's disappearance.
It is not known what triggered the latest search operation - the first in nine years - but the prosecutor for the city of Braunschweig, Christian Wolters, said they were acting on the basis of "certain tips".
Police said the search "resulted in the collection of some material that will be subject to the competent expertise", and that it would "be handed over to the German authorities".
The three day search ended on Thursday and a "relevant clue" was reportedly discovered in the area officers were focusing on - a 160 sq ft patch of woodland.
The spot is popular with drug dealers and partygoers, with Brückner reportedly selling cannabis to revellers in the remote woodland.
Wolters told German public broadcaster NDR the new information had not come from the suspect and they did not have a confession or "any indication from the suspect of where it would make sense to search".
Madeleine vanished shortly before her fourth birthday while she was on holiday in Praia da Luz with her parents. They had went out to dinner with friends, leaving Madeleine and her younger twin siblings asleep in their apartment.
Brückner is currently in prison for raping a 72-year-old woman in the same area of the Algarve from where Madeleine went missing.
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