Somehow you've managed to get the wrong end of the stick. At no point have I suggested that Wolters didn't speak for the whole investigation, quite the reverse. Read my posts; I am objecting to the suggestions that it has been driven purely by the BKA and that prosecutors only get involved when asked to decide whether to charge or not.
The German federal system is very different from ours and I don't think any definite argument is appropriate if a proper study hasn't been conducted allowing a modicum of understanding.
Nothing is cut and dried.
I don't think Google or Bild does the trick, really.
I believe that German prosecutors have to look at both sides of the argument. But ultimately that happens in Britain too as insufficient evidence = no charges and no prosecution. So the same but different.
As far as I know neither are German prosecutors truly independent. They are expected to report back to and take instruction from the relevant political minister.
The nuances are very different between our system, the Portuguese and the German. One size doesn't fir all.