Le Puritain

A religious fanatic finds his entire life and philosophy turned upside-down as he falls in love with a girl and kills her in a jealous rage. His search is for peace of mind and a desire to justify the murder of the girl to himself. His mind becomes distraught as he gropes trying to rationalize his deed and his world falls apart around him. A police inspector patiently and tirelessly stays on Barrault's trail, without putting him under arrest, though convinced he is the murderer, and waiting for the moment when he feels Barrault will break under the strain of his own religious fanaticism (IMDb).