While in agreement with the same caveat as to the reliability of the author expressed by the WS poster I've lifted this from I think it is worth noting in relation to the process the BKA may be using in building their case against Brueckner.
We are aware that Brueckner is a collector of photographic and video images. But I think it has dropped off the radar a little that he also fancied himself as an author and to that end had left word documents on the storage devices he secreted under his dog's corpse.
In Neuwegersleben, on January 14, 2016, CB’s neighbour calls the local police because of a nauseating smell that came from a certain place of the plot where CB resided in an autocaravan.
The stink was so intense that unlike the earth it did not freeze.
30 cm (1 ft) deep the police found the dead body of a Labrador and underneath it a LIDL supermarket bag containing firewood.
It was found and apprehended in the LIDL bag 6 pen-drives and 2 memory cards which contained “photos of children, including those of an unknown child in sensual poses and, mainly, Word documents which the police responsible for the find describe as writings about serious sexual abuse against children.
Later, BKA identifies these and other writings as two documents produced by the suspect with the titles of Das Buch and Das Buch 1. These books, said to be autobiographic, speak of himself and of friends and describe criminal practices.
It’s unknown if we are before realities or pure fantasies, but the fact is that the finding of all this material was and is useful for the construction of a suspect.
Chapter 26 Goncalo Amaral