Blackmail (1929 film)

Blackmail is a 1929 British film directed by Alfred Hitchcock, released in both silent and sound versions and generally regarded as the first British sound feature film, though production began as a silent picture before sound scenes were added partway through. Its story follows a woman who kills a man in self-defense after he attempts to assault her, then is blackmailed by a witness to the killing while her police-detective boyfriend investigates the crime unaware of her involvement. Hitchcock used the new sound technology experimentally, including a scene in which dialogue around the protagonist distorts to emphasize a single accusing word, reflecting her guilt.