This is one of those episodes the show tries way too hard to fit as many curveballs or plot twists as possible within 45 minutes which accomplishes the opposite effect of what is intended. The writers thought that forcing a bunch of unnecessary and unfitting plot twists and curveballs out of nowhere would keep the show "interesting" but they are actually an overkill and you lose interest in the show very quickly.
By the time the killer was revealed most viewers had no interest in the story anymore and couldn't care less who the killer is because they were utterly confused or bored of all those unnecessary curveballs which added nothing to the story. Curveballs are a useful plot device if they make sense and fit the overall story but when they are forced, they have the opposite effect where most viewers lose interest in your story.
By the time the killer was revealed most viewers had no interest in the story anymore and couldn't care less who the killer is because they were utterly confused or bored of all those unnecessary curveballs which added nothing to the story. Curveballs are a useful plot device if they make sense and fit the overall story but when they are forced, they have the opposite effect where most viewers lose interest in your story.