I guess it suits sceptics (aka Brückner apologists) to believe that no crime has ever been solved by one criminal lowlife dobbing another criminal in it, though there must be literally millions of incidences of such, whether they were incentizised or not, whether they waited years to spill the beans or not.
“Everyone thinks murders are solved by CSI type techniques such as fingerprinting, blood spatter analysis and so on but actually, sometimes murders are solved by someone banging on the door and doing the basic, traditional policing techniques. They are still the bedrock of those investigations." Dr Graham Hill
https://www.thesun.co.uk/news/20075456/murder-detective-madeleine-mccann-christian-b-graham-hill/We have been told that Brueckner actually was on police radar early days. They did bang on his door as a start, but for some reason or other they did not follow through.
One wonders was it because the police focus was so firmly fixed on Madeleine's parents that paedophiles/burglars were relegated and never given another thought.
Busching didn't know about Brueckner's claims until 2008 when he was apparently ignored by the police when he tried to report it. But even if any of the locally active criminal population had any suspicion of Bruckner, would the police have paid the slightest attention had they reported him.
I think not.
Because as far as they were concerned, they already had their woman!
When Brueckner's name first became known to us, Amaral was in the process of penning his second book still firmly pointing an accusing finger at people long since eliminated from any police inquiry.
The fact that obsession still ruled him and through him many others so many years down the line, suggests that the intransigence which dominated Madeleine's case right from the start actually did prevent any chance of solution.
Seems 'traditional policing techniques' Portuguese style, just weren't up to the job. Without Madeleine's case still being active and the German police alerted to him as a result, I think Brueckner would still be bouncing about from one end of Europe to the next totally in his element.