Quebec City locations and the earliest quickest Hitchcock director-cameo you'll see, the opening murder, Keller (O.A. Hasse) slinking away, encountering Father Logan (Montgomery Clift), opening "I Confess" (1953).
Very late one evening Keller asks if Father Logan will hear his confession. In the confessional, Keller confesses that he went to try to steal money from a person he gardens for, a rich lawyer called Villette, and in the process he killed him. Because of the binding nature of the secrecy of the confessional, Father Logan cannot tell the police anything he now knows about this crime.
At the time of the murder, two young girls saw someone leaving the house of the murdered man wearing a cassock. While this was just Otto's disguise, suspicion falls upon Father Logan himself (who cannot provide an alibi for the time of the murder, cannot talk about the confession he heard, and cannot name the true murderer).