Perhaps the magnum opus of Dario Argento's giallo films, this tightly directed, well acted, and amazingly scored (thanks to Giorgio Gaslini and Goblin) affair brings a true sense of mystery to scale. George Hemmings acts his butt off as jazz pianist and witness to the gruesome murder of Helga Ulmann (Macha Meril), Marcus Daly. With the police failing to discover any clues, Daly strikes up a dalliance with local reporter Gianna Brezzi (Daria Nicolodi). Gianna comes to the aid of…