Complex sentence: Even Alfred Hitchcock, whose own films inspired the genre, was influenced by the "giallo" in his later career as evidenced by his penultimate film, "Frenzy" (1972).
Split into simpler sentences: Even Alfred Hitchcock, whose own films inspired the genre, was influenced by the "giallo" in his later career. This was no more evident than with his penultimate film, "Frenzy" (1972).