I think the Germans are determined as far as Madeleine's case is concerned; but I don't think they are in any great hurry to go after Brueckner who I think may be part of a bigger picture of concern.
Police worldwide are spending a lot of time dealing with paedophile cybercrime with the aim of rescuing abused children; Germany is no stranger to that following reports at the beginning of the year of a paedophile ring with perhaps up to 30000 subscribers.
They may also be taking a proactive role in response to appeals for tougher sentencing for such crimes from countries such as the Philippines.
Snip German man sentenced to five and a half years for livestreaming sex abuseIn one of Germany's first major prosecutions for webcam sex abuse, a man has been handed a hefty sentence. It comes after the Philippines called on wealthy countries to help crack down on the problem.
https://www.dw.com/en/german-man-sentenced-to-five-and-a-half-years-for-livestreaming-sex-abuse/a-43330106In response to the oft asked question "Why Madeleine? Why not all the other children?" These are the other children and the police are trying to do something about them all without the necessity to turn it into a vigilante witch hunt.
We are told that Brueckner has an internet presence on sites such as these. So there may be a long and arduous investigation pertaining to all aspects of his internet activities. I don't think that will be a short term endeavour (unless they have already got that evidence) so I'm not holding my breath for charges to be laid against him any time soon and particularly for as long as he remains safely under lock and key.
I think the German police and I am sure Scotland Yard have a huge and complex situation here involving thousands of children some of whom will never be identified as none are as recognisable as Madeleine. So long term it is prudent to remember that someone is aware of them and trying to help them if they can and I think Madeleine's case has helped not hindered in that process.