Triptych for a Witch

CBS Radio Mystery Theater "Triptych for a Witch" is a Mystery from Thursday, October 30, 1975.

Joan Madden and her husband Walter receive an unexpected visit from Joan’s great aunt, Hester, recently widowed by a tragic fire. Although Walter senses something strange about Hester, he invites her to join them on a shore vacation. When Walter thinks he sees Hester’s pet cat change into the form of its mistress, he becomes convinced she is a witch. When he discovers that Hester has been collecting a rare type of poisonous seaweed, he suspects Joan’s life may be in danger.