The witness for the prosecution, a surprise witness, is Christine Vole (Marlene Dietrich), presumably the wife of the man on trial for murder, Leonard Vole (Tyrone Power), a ne'er-do-well gadget peddler. She claims that she is not legally Leonard's wife, then refutes his alibi. The next day, however, Leonard's counsel, Sir Wilfrid Robarts (Charles Laughton), destroys Christine's testimony with a small bundle of letters that she had written to her "Beloved Max" in Germany, and consequently wins Leonard's acquittal. The trial over, Christine tells Sir Wilfrid that she knew Leonard to be guilty all along, that she, disguised, had tricked Sir Wilfrid into taking the phony letters the night before, perjuring herself in order for Leonard to be freed. When Leonard appears with a young, pretty blonde (Ruta Lee) and announces that he plans to go away with her, Christine, enraged, stabs Leonard there in the courtroom, using the knife presented in evidence as the murder weapon. Sir Wilfrid then makes plans to defend Christine against the charge of murder.
The multifaceted trick ending of Agatha Christie's original play made it highly popular in London's West End and on Broadway, where it ran for almost two years. Although the play was done as a straight mystery, Billy Wilder and Harry Kurnitz in their screenplay insert a good deal of humor and emphasis on character, their main addition being Miss Plimsoll (Elsa Lanchester), Sir Wilfrid's private nurse, the source of some of the finest comedy in the film. At the time of this film Wilder had earned considerable fame for a group of excellent films noirs that began with Double Indemnity in 1944; and in the 1950's and early 1960's he was highly regarded also for his dark comedies such as Stalag 17 (1953) and misanthropic farces such as The Apartment (1960) and Kiss Me, Stupid (1964). Witness for the Prosecution combines the usual Wilder touches—masquerade, verbal wit, intimations of a corrupt environment—but emerges one of his lightest, least trenchant works, without denying in the end the reality of human baseness.
The film's effect depends upon misleading appearances, things turning out to be not what they originally seemed. The climax follows smoothly from the deceptions, not all of them malicious, that run throughout the various relationships within the story.
The humor in the film derives largely from the attempts of Sir Wilfrid, recovering from a coronary, to outwit Nurse Plimsoll, his "jailer" (he calls her) and the surrogate for his doctor, who has forbidden him a number of amenities, including participation in murder trials. Sir Wilfrid plays the naughty school boy to Miss Plimsoll's matron. He evades her naps, shots, pills, and, especially, injunctions against cigars and brandy. His antics extend to outright rebellion the night he receives the phone call from the mysterious cockney woman about the letters, as he rushes off -to Euston Station after grabbing Miss Plimsoll's poised hypodermic and sticking it in the end of his cigar. Her browbeating and smothering attention, however, give way finally to pride and admiration at Leonard's trial: "Wilfrid the fox—that's what they call him" she proclaims to everyone in the balcony when Sir Wilfrid confronts Christine with the letters. She is also the one who orders the return of the luggage from the boat train, decisively announcing that Sir Wilfrid will appear for the defense of Christine. He has never really fooled her, anyway, as she makes clear when she reminds him that he has forgotten his brandy (his thermos of "hot cocoa"). Their growing camaraderie furnishes a healthy, innocent contrast to the treachery, both real and feigned, that marks the Voles's relationship.
Christine's deceptions underlie the major part of the film's climax. She bears out Sir Wilfrid's initial suspicion of her when she appears for the prosecutor Mr. Myers (Torin Thatcher), claiming that she was already married to a man named Helm when she went through a ceremony with Leonard in Hamburg while he was serving with the British occupation forces after World War II. Her testimony proves in fact no deception at all—Leonard did return home late on the night in question with blood on .his clothes, admitting that he had murdered Mrs. French (Norma Varden)—although at the time it seems to be outright betrayal. She sounds convincing enough, particularly after Myers admonishes her in her own language about perjury, Meineid. In spite of Leonard's artless rebuttal, the jury members, as Brogan-Moore (John Williams) points out later, did not like Christine but believed her, whereas they liked Leonard but did not believe him.
Christine's tour de force of deception and disguise is her impersonation of a cockney trollop at Euston Station. She readily convinces both Sir Wilfrid and Mayhew (Henry Daniell) that they are interviewing a woman wronged by Christine Vole, who stole her lover and caused him to disfigure her right cheek. "Wanna kiss me, Ducky?" she asks Sir Wilfrid, pulling back her hair to show him her scar. In court the next day she continues her deception as Sir Wilfrid, with one of the bogus letters in hand, meticulously exposes her commitment to Max and her plan to give false testimony against Leonard. She follows through until after Leonard has been acquitted, even though some of the spectators physically abuse her as she tries to reach Leonard and Sir Wilfrid.
Leonard's masquerade is equally as expert as Christine's. Like his wife, he must hoodwink Sir Wilfrid at close quarters. In the initial conference Leonard Wins Sir Wilfrid over, presenting himself as a sincere, talented young inventor, the victim of unfortunate circumstances. Sir Wilfrid decides to rescue him when Brogan-Moore as well as Christine show hesitation about his innocence. Already Leonard had convinced Mrs. French, a wealthy, middle-aged, lonely widow, that he would marry her, or convinced her of something that caused her to change her will and leave him eighty thousand pounds. Christine apparently knew little enough about the details of that relationship, and certainly nothing at all about his involvement with Diana, his blonde girl friend.
To give the story pace and to lead up to the action of the trial, Wilder uses flashbacks that fill in Leonard's relationship with the murdered woman and with his wife. Since the two episodes are narrated by Leonard, they lend credibility to his story. He tells how he happened to see Mrs. French from outside a milliner's shop, where he volunteered advice on a new hat, then in a cinema, and of their ensuing friendship and the encouragement she gave him for his inventions. He also tells of his first meeting with Christine, in the midst of a brawl, at the Hamburg cabaret where she performed. The fight had broken out when, after she sang a song, some of the patrons began to quarrel over her (presumably the sequence was thus staged in order to give the audience a glimpse of the famous Dietrich legs).
Wilder never lets the story become introspective: he mutes the tension between devotion and perfidy by keeping the audience entertained with various gimmicks. Witness for the Prosecution has an intelligent balance of courtroom drama, suspense, multilevel humor, and consummate acting. Wilder allows his actors a good deal of freedom. Power makes Leonard a sympathetic although basically shallow character. Just as Leonard seems incapable of stabbing a defenseless woman, his anguish and confusion during the trial appear symptomatic of an engaging naïveté. Yet he readily gives way to the smug callousness that his acquittal uncovers in him. Marlene Dietrich's Christine embodies the right amount of iciness, mystery, and, in the cockney interlude, low comedy. She does overact embarrassingly when Sir Wilfrid destroys her on the stand and when she finally avenges herself on Leonard. On the other hand, Elsa Lanchester performs at her best as the irritating but loyal Nurse Plimsoll. She shows excellent rapport with Laughton, whether coddling him, berating him, or admiring him.
Witness for the Prosecution nonetheless becomes Laughton's film: his Sir Wilfrid binds all together as he romps through each of his scenes. He bullies and cajoles, grimaces and smirks, assailing the veracity of witnesses by reflecting the glare from his monocle into their eyes. Surely the funniest episode in the film is his cross examination of Janet McKenzie (Una O'Connor), Mrs. French's testy, practically deaf Scottish housekeeper, who hates Leonard for working his way into her mistress' will and thus cheating her out of her share. Sir Wilfrid maintains his owlish dignity when he recognizes that Christine and Leonard alike have thoroughly duped him. Even though he suspected something because the solution turned out too pat, he admits that he never suspected Christine's masquerade. He is aghast after she asks him once again, in her cockney dialect, if he wants to kiss her. Yet he passes over defeat into a new challenge, Christine's defense, for she did not actually murder Leonard—"she executed him" he solemnly tells Miss Plimsoll.
Its surprise conclusion aside, Witness for the Prosecution appeals as a well-made, coherent melodrama whose performances engage at least as much as does the plot. It is a handsomely designed production, done almost entirely in interiors, the sets for the courtroom in the Old Bailey and for Euston Station, particularly, giving it a thoroughly London atmosphere. The film was Power's last; he died a year later at the age of forty-four while filming Solomon and Sheba (1959), and his scenes were reshot with Yul Brynner. Laughton would make three more films, but in none would he get the opportunity to exhibit the range he does here, not even portraying the wily Senator Cooley in Preminger's Advise and Consent (1962), his final role. As Sir Wilfrid, one reviewer noted, "the old ham has found the right platter." Sir Wilfrid plays off excellently against Leonard: he becomes defender, then antagonist, of a killer who has ingratiated himself into a tremendous amount of loyalty from two older women. Mrs. French leaves him her fortune, and Christine sets herself up for a perjury conviction and a prison term in order to ensure his freedom. "The wheels of justice grind slowly," Sir Wilfrid admonishes Leon¬ard at the end, "but they grind finely."
Justice comes unexpectedly through the hand of a spurned woman. Leonard understands his acquittal as a piece of good luck and as the payment due for his bringing Christine out or Germany. Years of marriage have, however, failed to teach him an important thing about his wife, for if he accurately calculates the,,depth of her loyalty, he fails to reckon with the extent of her jealousy. All sympathy finally goes to Christine, whose acquittal seems assured with Sir Wilfrid by her side.