The Mad Ghoul

The Mad Ghoul 1943 is a science fiction and Universal monsters horror film, also known as Mystery of the Ghoul, starring Turhan Bey, Evelyn Ankers, and David Bruce, and featuring George Zucco, Robert Armstrong, and Milburn Stone.

Later, on the night of the duos first experiment, Ted brings Isabel to Morris house, where Morris notices Isabels discomfort about her relationship with Ted. He confers with Isabel, saying that she does indeed need a man more involved with her love of music, secretly meaning himself. Isabel, however, is afraid of hurting Teds feelings and getting him to understand what she wants, but Morris promises to take care of the situation himself. Unbeknownst to Isabel, Morris evil plan involves destroying Ted by exposing him to the lethal Mayan gas the next day, and in effect, making him a mindless ghoul who, like Choco, must continually rely on the fluid of human hearts to survive obtained by performing cardioectomies on freshly dead persons. This sets Ted and Morris on a killing spree through several towns where Isabel is also performing on her tour. Morris tries to get Ted to return home, but Ted is committed to being with Isabel whenever possible, whenever he is not in his unknowing ghoulish state. But, when Ted turns back into his ghoulish state, Morris once again uses him to try attempt to kill off the one person Isabel truly seems to loveEric Iverson Turhan Bey, her partner and pianist. Although his attempt is unsuccessful, Ted is able to obtain another heart, keeping himself alive.Eventually the police, aided by ace reporter Scoop McClure Robert Armstrong, realize that the mysterious ghoulstyle killings are on the same route of Isabels tour. McClure tries to set a trap in Scranton, the last city of Isabels tour, by making it seem to the public that he is someone else who has recently died, and, by waiting in a coffin for the ghoul, nearly captures Ted and Morris once they arrive to perform another cardioectomy. However, Morris distracts McClure as Ted comes into view and kills him. ........

Source: Wikipedia