The Witches (1966)

An English school missionary assigned in an African village has a run-in with the local witch doctor and suffers a nervous breakdown. After recovering back in England, she takes a job teaching in a small country town, hoping to make a new start for herself. All goes well at first, until she starts to hear disturbing stories about the town. She soon discovers that the town is home to a coven of witches who plan to sacrifice a local girl in one of their rituals.