Morgiana
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.
Directors: Juraj Herz
Writers: Aleksandr Grin, Juraj Herz, Vladimír Bor
Cast
IMDB: tt0124012