53x9 - Scene of the Crime

What begins as a completely "normal" murder investigation takes on ever wider ramifications: The shopaholic Magnus Rosponi is found beaten to death in his apartment. But neither his cheerful bowling friends nor Silke Haller, who recognizes the dead man as a teenage crush, can explain why the popular man had to die. Instead, Professor Boerne finds a strange, small object in the corpse. Thiel discovers parallel amorous entanglements. And when the Federal Office for the Protection of the Constitution turns up in the shady characters Muster and Mann, things get absurd. Apparently Thiel and Boerne have stirred up a hornet's nest and even attracted the attention of an assassin. But how is it all connected? And what's the story with the little dog that loves eating bananas?