Defense de savoir

When the police find Simone seated near her husband's corpse it is predictable that she is charged with the murder. Jean-Pierre Laubray is appointed counsel for the defence. He begins an inquiry into the case and he finds out that the murdered man had killed a barman in a robbery the night before. He finds out as well he was a leg-man of Cristiani's for his election campaign. He tries to contact Juliette, Cristiani's daughter, and he discovers that also Bruno, Juliette's brother, died that same night in a car accident...