Sabotage

Sabotage, also released as The Woman Alone, is a 1936 British thriller film directed by Alfred Hitchcock. It was based on Joseph Conrad's novel The Secret Agent. Karl Verloc (Oscar Homolka), the owner of a cinema, is part of a gang of saboteurs from an unnamed Europe country who are planning a series of attacks in London. The exact motives are not clear to us. Scotland Yard suspects Verloc's involvement, and assigns Detective Sergeant Ted Spencer (John Loder, who replaced Robert Donat, who was too ill from asthma to play the part), to investigate (initially undercover) Verloc. Ted Spencer conducts the undercover investigation posing as a greengrocer's helper, selling fruits and vegetables in the shop right next to the cinema. Verloc's young and beautiful wife (Sylvia Sidney) believes he is a good man who has been kind to her and her little brother in the past. However gradually she comes to suspect that her husband may be one of the people who are behind the attacks which are... full article at wikipedia