The Penitent Man (S05E15)

Flambeau is incarcerated under suspicion of murder. When Father Brown visits him he denies killing his cohort Flynn and asks the priest to hear his confession if he's convicted. Flynn's wife Peggy later tells Father Brown that she witnessed Flambeau dragging Flynn's body to the river and throwing it in. At the presbytery, Mrs. McCarthy thinks that Flynn is still alive and has framed Flambeau. Father Brown leaves the surveillance to her and Bunty while he attends Flambeau's pre-trial hearing. He's shocked to hear Flambeau plead guilty then be sentenced to death by hanging. (iTunes)