Dementia 13 a 1963 Francis Ford Coppola/Roger Corman slasher film, is available for download from Archive.org. From Wikipedia:
Dementia 13 is a 1963 horror thriller released by American International Pictures, starring William Campbell, Patrick Magee, and Luana Anders. The film was written and directed by Francis Ford Coppola and produced by Roger Corman. Although Coppola had been involved in at least two nudie films previously, Dementia 13 served as his first mainstream, "legitimate" directorial effort. The plot follows a scheming young woman who, after having inadvertently caused the heart attack death of her husband, attempts to have herself written into her rich mother-in-law's will. She pays a surprise visit to her late husband's family castle in Ireland, but her plans become permanently interrupted by an axe-wielding lunatic who begins to stalk and murderously hack away at members of the family.