Le bal masqué

At a petrol station, a middle-aged couple is brutally murdered for no apparent reason. Before tearing off with screeching tires, the assailants steal important documents from the victims' Mercedes. Police detective Daerden, who is conducting an undercover operation at a nearby night club, drives to the scene of the crime and is also hit by the gang. That same night, investigating magistrate Siccard arrives and questions Daerden.