Black Sabbath Movie Wiki

 Rosy sleeps, Mary gets up out of bed and pens a note of confession: she was the one making the strange phone calls when she learned of Frank's escape from prison. Knowing that Rosy would call on her for help, she explains that she felt it was her way of coming back into her life after their breakup. While she is busy writing, she fails to notice an intruder in the apartment. This time it is the real Frank. He creeps up behind Mary and strangles her to death with one of Rosy's nylon stockings. The sound of the struggle awakens Rosy and she gasps in fright. The murderous pimp realizes that he just killed the wrong woman, and slowly makes his way to Rosy's bed. However, earlier that night, Rosy had placed a butcher knife under her pillow at Mary's suggestion. Rosy seizes the knife and stabs Frank with it as he's beginning to strangle her. Rosy drops the knife and breaks down in hysteria, surrounded by the two corpses of her former lovers.Black Sabbath  Movie Wiki