The Long Dark Hall is a crime drama starring Rex Harrison and his real- life wife (at the time), Lilli Palmer, who in the film, play husband and wife, Arthur and Mary Groome.
This seems to be a story within a story as told by a newspaper reporter to a crime novelist. But, the internal story is the one that I focused on throughout the movie.
In this story, Arthur and Mary Groome appear to be a happily married couple who live in Richmond with two young daughters. However, when a London showgirl is found dead on a night that Arthur visited her—which he admitted to everyone that he often did--he is accused of her murder. Yet, he claimed he did not kill her, and his wife, Mary, totally believes him.
His accusation and trial for her murder is based on a ton of circumstantial evidence, including his knife at the scene, witnesses, and her blood on his suit (which he admits, he in the trial, that he burned because it couldn't be dry cleaned)....