Robert Siodmak, 1946
Starring: Olivia de Havilland, Lew Ayres, Thomas Mitchell
A doctor is murdered and the main suspect is his girlfriend. When Lt. Stevenson goes to question her, he learns that it is actually two girls, identical twins – Terry and Ruth Collins – and that they have an airtight alibi because of it. He knows one of them is guilty, but doesn't have any evidence. He receives some assistance from a psychiatrist, Dr. Elliott, who convinces the girls to undergo a few weeks of testing. He falls in love with Ruth and comes to believe that Terry is psychopathic and dangerous and learns that her trigger is jealousy. He's realizes that he and Terry are both in danger, but can he prove which twin is which?
With a compelling script from Nunnally Johnson (The Three Faces of Eve) and competent, stylish direction from Robert Siodmak, The Dark Mirror is an underrated effort that waves between mystery, noir, and melodrama. Similar to other film noir from the period, like Otto Preminger's Whirlpool (1949), the film includes several popular themes, such as a romance where a man falls in love with a troubled woman and endeavors to save her, and some very heavy-handed instances of psychiatry and Freudianism. It also fits in with “women’s pictures” like Mildred Pierce, The Reckless Moment, The Letter, and many others. One of the things that sets The Dark Mirror apart is an excellent, subtle performance from Olivia de Havilland (The Died with Their Boots On, Gone with the Wind).
The murder mystery is the least interesting thing about the film. It's obviously that one of the twins must have killed the doctor, but De Havilland is able to rise above this fairly trite plot device with the subtle differences she invests in Ruth and Terry. The spectacle of twin-ness, and even more so, of femininity, becomes the film's centerpiece. Though it is suggested that the concept of twin-ship is unnatural, it puts more of an emphasis on the fact that the twins are women and their femininity is where the true perversion lies. The murder and violence is based on the inherent jealousy and possessiveness of women, which is bleakly misogynistic, but still makes for an interesting look at female mental illness. Good and bad siblings feature in some of Siodmak’s other films, including Son of Dracula and The Spiral Staircase, where psychopathy also lurks behind an attractive façade.
De Havilland apparently had a real life feud with her sister, actress Joan Fontaine, and she brings every ounce of that to the screen. There's a palpable lesbian undercurrent, as it is clear that Terry becomes homicidally jealous every time a man prefers Ruth. She is determined to keep Ruth all to herself, and to be viewed as the smarter, stronger, and more beautiful twin. To enhance this battle between identities, Siodmak borrows liberally from German expressionism, which was reliant upon doubles, mirrors, and reflections. Perhaps the film's finest moment is that it ends on an eerie, uncomfortable note, suggesting that it's unclear which twin remains to live out a happy, romantic life with Dr. Elliott.
In addition to De Havilland, there are some solid supporting performances. Thomas Mitchell (It's a Wonderful Life) is memorable as the stalwart detective who doesn't fall for the twin's ruse for a moment and is convinced that one of them is a dangerous killer. Lew Ayres (All Quiet on the Western Front) is a little disappointing as the somewhat creepy, inappropriate doctor. This marked Ayres shaky return to cinema and he was still iffy in the eyes of fans. Perhaps ironically, his performance in All Quiet on the Western Front made him staunchly anti-war. He declared himself a conscientious objector, to the horror of cinema-going Americans. For a few years, he was blacklisted, despite the fact that he served as a medic in the South Pacific.
The Dark Mirror may not be a film noir classic, but it is well worth seeing thanks to De Havilland and Siodmak. Though it is from the '40s, it's aged very well, probably because the concept of twins as the source of a mystery is a concept that hasn't grown old. The film is available on Blu-ray, perhaps surprisingly, and fans of Dead Ringers and especially Sisters will want to check this out – Sisters in particular feels like a direct rip off of The Dark Mirror. A double feature of the two would probably yield some fascinating results.