Morgiana(1972)

movie - first aired/released 1972-09-15 - audience 7.2

Jealous of her vapidly "good" sister's popularity, poisonous Viktoria doses pretty Klara's tea with a slow-acting fatal substance. As the latter grows hysterically weak, the former finds success increasingly compromised by guilt, blackmail, and the pesky need to kill others lest she be exposed.