This time I was very wrong about the killer lol. I immediately thought about the manager, but it seemed too obvious, so I was wondering if Suwa was the mother of the girl accidentally killed in the third story by a police officer. I had immediately understood that Hayami had kidnapped Reika based on the photo and then on her fear of the scarf, but at the same time if Suwa had been the culprit it would have meant that he was also involved in the third case, which was unlikely... still, the manager looked like the most suspicious person so I kept thinking "it can't be him, it must be someone you'd never expect". Oops!