Adored this Film

I love the giallo genre, have seen dozens by all the major auteurs, and one thing I can say about every Sergio Martino film is that I can never predict what's gonna happen next, or what the ultimate payoff will be. I watched this back-to-back with "The Strange Vice of Mrs. Wardh" and was still blown away by the identity of the murderer and the intricacies of the plot. I guess I'm too similar to Detective Germani in Argento's "Tenebre" -- as familiar as I might be with the tropes of the genre, I can never guess who the killer is. But dang: Martino is a criminally underrated master.