Murder Rock (1984)
Murder Rock (Italian: Murderock - uccide a passo di danza; also known as Murder-Rock: Dancing Death, Slashdance and The Demon Is Loose) is a 1984 Italian giallo film starring Olga Karlatos and written and directed by Lucio Fulci. Fulci recalled the producer forced him to turn the film into a musical with the music of Keith Emerson due to the success of Flashdance.
More at Wikipedia.