The weakest part of Shadow of a Doubt, a movie directed by Alfred Hitchcock, is the part that involves the detectives. Nothing really seems to make sense. They want a picture of Charlie Oakley (Joseph Cotton) so they can show it to witnesses to see if he is the Merry Widow serial killer. All they need to do is bring him in for questioning and take his picture. Failing that, they could have photographed him when he walked right toward them at the beginning of the movie. After he walks past them, they follow him. What for? Do they think that by following him, they will catch him in the act of killing another widow? I could go on, but what would be the point? Suffice it to say that everything involving these detectives is unrealistic. And it is a shame, because with a few changes in the script, they could have been left out entirely.
It is the rest of the movie, the parts where the detectives play no significant role, that the movie really engages us. When the movie begins, it is clear that Charlie Oakley has just killed another widow, after first getting his hands on her money. But it is not the money he cares about. He hates these women and it gives him great satisfaction to kill them. But now, thoroughly sated from his recent murder, he is weary, listlessly lying in bed, with some of the money carelessly allowed to fall on the floor. He finally decides to visit his sister and sends her a telegram.
Meanwhile, his niece, young Charlie (Teresa Wright), is first seen lying supine in bed in a way that matches her uncle when we first saw him, giving us just a hint of incest. Her fascination with her uncle is just a little unsettling in this regard. They both have the same name, and she is convinced that they are just alike, that they have a special connection between them. At first, she too is listless, just as her uncle was, but she suddenly decides to send him a telegram, inviting him to visit them, right after he has sent her mother a telegram saying that he is coming.
When her uncle arrives, he gives her a ring, which has an engraving on the inside, “T.S. from B.M.” Later, Charlie reads in the paper that the initials of the deceased husband of a recently murdered widow were “B.M.” Both “T.S” and “B.M.” are well known abbreviations for fecal matter, which is a way of suggesting something foul associated with the beautiful emerald ring. The evil hidden underneath beauty is the theme of this movie.
In a similar way, the town where young Charlie lives is one of those warm, wholesome towns, representing the goodness of America, and good-looking Uncle Charlie is the evil hidden within that town. But that is not the most disturbing example of this theme. We find such evil in young Charlie herself. As the movie keeps emphasizing, and as she keeps insisting, she and her Uncle Charlie are very much alike. And that means that she has her dark side too. Because young Charlie is played by Teresa Wright, a wholesome looking young woman, rather than an actress whom we might see playing a femme fatale in a film noir, the contrast between her innocent appearance and the evil within her is stark.
When she figures out that her uncle is the Merry Widow murderer, she does not turn the ring over to the police and tell them what she knows. Instead, she merely insists that he leave town, so that her mother will not be hurt by the knowledge of what her brother really is. And she does this even when she knows who his next victim will be, a widow he meets in town, and who will be leaving on the same train. This would have made her an accomplice to his next and subsequent murders had he simply left town as she wanted.
In another scene, she tells him that she wants to kill him. And so she does. The scene in which she pushes her uncle into the path of the oncoming train can be understood as merely the accidental result of her effort to get away from him, and it would have been an act of self-defense in any event. But what happens matches what she says she wanted to do. Of course, there is no way her dark side is anything like that of her uncle, the main difference being that her uncle had a head injury when he was young, which allowed his dark side to flourish. But the evil in her is there nevertheless. And so, the movie seems to say, in all of us.