The Night Angel (1931)

In this crime drama, a Prague DA must close down a house of prostitution masquerading as a cafe. He sends the owner's daughter to a nurse's home until her mother is released. When the happy day comes, he goes to visit them, but is attacked by the doorman, who is in love with the daughter and jealous of the DA. The DA kills him in self-defense but is acquitted when the daughter delivers a highly emotional speech professing her love for him.