Blood Mania [1970]

Dr. Craig Cooper is caring for the director of his medical practice, Ridgeley Waterman. At home with her ailing father is his flirtatious daughter Victoria. She is more interested in winning the attention of Craig than meeting her father's needs. A corrupt colleague from Craig's past shows up and demands $50K to keep his silence about some illegal abortions that Craig performed when short of funds. This provides Victoria with a means to gain Craig's gratitude. She tells him she can come up with the money. He is hugely appreciative, but doesn't realize that she means to hasten her father's death to get at her inheritance. Victoria uses an ampule of amyl nitrite to cause her father's heart condition to turn fatal. Her glee is short-lived because when her father's will is read, he leaves the bulk of his estate to her estranged sister, Gail, who returns from New York for the event. Victoria loses control, and in a fit of rage, murders her sister. Craig helps dispose off the body. Things are still not settled, the blackmailer is at the door awaiting his $50K.