While Brueckner may be cocksure that there's no evidence to be found of him having carried out any crimes against Madeleine, here's a little reminder of part of the BKA appeal from June 2020.
"Furthermore, there is reason to assume that, in addition to the perpetrator himself, there are other people who have specific knowledge of the possible course of events and, if applicable, where the corpse was deposited. We expressly ask these people to get in touch and share their knowledge."
https://www.bka.de/DE/IhreSicherheit/Fahndungen/Personen/BekanntePersonen/43_Jaehriger_Deutscher_TV/Sachverhalt.html?nn=26874#detailinformationen132470After 3 years of police investigations involving many officers (not a small team of documentary makers researching for a few months) BKA must have had a good reason to make that assumption.
Brueckner has written several letters to different people citing reasons why the BKA have got it wrong in the various crimes he's been accused/convicted of. It's almost like he doesn't trust Schwenn & Fulscher to help prove his innocence in the Madeleine case.