Gengæld (1955)

The widow Elise lives in a large villa with her adult son Eigil and their tenants, among others an impoverished writer and a rich manufacturer. One day a certain Mr. Schmidt comes to visit and claims to be Eigil's father. Elise denies it, but that's not the only secret Schmidt thinks he has. And before the evening is over, the villa is transformed into a crime scene.