Professor Charlotte Hartmann suffers fatal cardiac arrest due to a blocked sauna entrance. Charlotte's boyfriend, sauna manager Marcel, is shocked and points at ex-con voyeur Ronny Ludwig, whom he caught taking nude pictures of her from outside. The latter in fact tried to unlock her, but was duly afraid as the team has a hard time believing him, although he lacks motive. Charlotte actually booked a romantic Turkish bath-treat for two with fellow professor Stephan Pohl, which Marcel ignored, but not his employee Melanie Meyer.
—KGF Vissers