This novella by Linwood Barclay was OK. The point of the mystery is only partly to do with whodunnit, which is a good thing as there are little clues all over the place from the get-go. No, the bigger point is what will be the outcome of the interaction between the characters. Unfortunately, I couldn’t care less about any of them, and in a mystery like that, you need to care somewhat in order to enjoy the suspense and have it do for you what suspense is supposed to. It was like watching a swim meet final where no Canadian is entered: it’s something to pass the time, but you’re not vested in it.
Having said that, the message at the end is pointed and makes you think, “if only…”