Scotland Yard said on Friday its investigation into Madeleine McCann’s disappearance continues despite a German national being made a “formal suspect” by Portuguese authorities.
Brueckner, currently jailed in Germany for rape, was told of the development in his cell on Wednesday, sources said.
Investigators believe he killed Madeleine, then three, after abducting her from a holiday apartment in Praia da Luz in May 2007. She was staying there with her parents Kate and Gerry McCann, of Rothley, Leicestershire.
Brueckner was identified as a murder suspect by German prosecutors in June 2020 but not charged since then.
The Metropolitan Police continue to treat Madeleine’s disappearance as a missing persons inquiry.
A final funding request for Operation Grange - launched in May 2011 - was recently submitted to the Home Office, taking it to the end of September.
The probe will be wound down unless significant new information comes to light. The total cost of Op Grange is approximately £13 million.
Jim Gamble, the former head of the Child Exploitation and Online Protection Centre, who worked on the investigation into Madeleine’s disappearance, told BBC Breakfast: “Well, this breakthrough could mean everything or it could mean nothing.
“My own gut feeling on it - from the moment the Germans began to release information two years ago - was that this was the best fit.
“You have proximity, you have opportunity, and you have a profile with regards to an offender that absolutely fits in a way that no others have.”
He added: “This is all positive. And from my own position, and I wouldn’t be surprised if charges did follow.”
A statement issued yesterday by the Portimao section of the Faro department of criminal investigation does not name Brueckner, but says the person was made an arguido by German authorities at the request of Portugal’s public prosecution service.
It says the investigation has been carried out with the co-operation of the English and German authorities.
German newspaper Bild reported that Brueckner’s lawyer Friedrich Fuelscher said the Portuguese decision appeared to be a “procedural trick”.
Reports suggested the move could be linked to the country’s statute of limitations, which does not generally allow crimes which carry a maximum prison sentence to be prosecuted more than 15 years after they were committed.
This would mean Brueckner could no longer be charged in Portugal after May 3.
Brueckner, referred to as Christian B in Germany due to the country’s strict privacy laws, was found guilty in 2019 of the 2005 rape of a 72-year-old American woman in Praia da Luz, and sentenced to seven years at a court in Brunswick, Lower Saxony.
Portuguese sources have said the legal grounds for making Brueckner a suspect include allegations he confessed to a friend he had snatched Madeleine and mobile phone records placing him in Praia da Luz the night she vanished as her parents ate a tapas meal nearby.
The German drifter who spent several years living on the Algarve was jailed for petrol theft in 2006.
Madeleine’s parents, and British-Portuguese property consultant Robert Murat, were made arguidos in September 2007 but later cleared.
A Met spokesman on Friday referred all enquiries to the Portuguese authorities and said funding for Op Grange was “for the Home Office to determine”.