The motivations and behaviors of most of the characters are either random or studid. You cannot make every character in a book crazy / disturbed / disfunctional! It would make no less sense to have any one of the suspects turn out to be the killer, based on a quick rewrite of a few paragraphs. That's not the way a mystery is supposed to work. Too many times, the heroine acts in a way that makes sense only because it will further complicate the plot. Surely no woman would have created this pathetic character. Probably the worst "thriller" I've ever actually finished (saving it from a 1 star rating).