This 1946 film Dark Mirror stars Olivia de Havilland as twin sisters, one of whom has committed a murder. Since each twin can provide an alibi for the other, a rumpled detective (Thomas Mitchell) and a handsome shrink (Lew Ayres) are compelled to get to the truth, a task not made easy by the sisters. At first the twins seem physically and emotionally similar. Subtle nuances differentiate their personalities and it is De Havilland's fine acting that peels away the layers of emotionalism that define each sister's character traits. De Havilland, aided by keen camera work by Siodmak, keeps viewers on edge as she shifts roles within frames that are shared by both sisters.