Father Brown - Season 3 Episode 13

Whilst Father Brown and Mrs McCarthy are in the bank there is an armed hold-up but the robbers flee after the vault is opened to reveal the corpse of Billy Flanders, shady son-in-law of bank manager Samuel Harrogate. A note in the dead man's pocket incriminates Harrogate and Sullivan arrests him. Father Brown however realizes that the two bank clerks stand to gain by the manager's removal and later recognizes one of the robbers who tells the priest who planned the robbery. Father Brown comes to wonder why it was so important that he witnessed the failed heist before coming to discover the murderer's identity.