By the way, when writing novels, I completely agree it is vital to make the audience feel cleverer than the characters in the story. This is particularly true with whodunit type narratives. In my own gothic mystery horror/thriller novels, if there is a murder to be solved, or a mysterious figure to otherwise be unmasked, I have one character that is suspected by the protagonist, so the reader will know it obviously can't be them, as all the evidence points that way. I will create a second (or indeed, third, fourth, and fifth) character for the reader to suspect, so they can feel superior to the protagonist. Then of course, there is a final character who turns out to be the killer (or who is unmasked for some other reason), that is hiding in plain sight; a solution that ought to have been obvious from the start, but the reader placed them above suspicion.