You do like to pick and choose who you believe don’t you, why should this successful Met detective be any more credible than any other successful Met detective, or succesful German prosecutor for that matter? You appear to believe Sutton without question but doubt everything that Wolters says for example.
Sutton had never worked on Madeleine's case and had absolutely no idea how it was conducted. I doubt very much if he had any real idea of how absurdly obdurate some of the Portuguese counter parts were capable of being.
Brueckner was a work in progress for Wolters which Madeleine became part of. Confirmed photographic evidence was that Brueckner abused children. Madeleine and Praia da Luz then became the focus of part of a wider reaching German investigation.
Therefore approaching Madeleine's case from a different angle and with fresh eyes was as a result of investigating available evidence involving the Praia da Luz rapist.
Madeleine's parents did not feature ... but Brueckner became prime suspect in Madeleine's disappearance as a result of evidence + investigation = suspicion.