In 1960, up-and-coming screenwriters Richard Levinson and William Link were hard at work expanding a mystery script they’d written into a full-length stage play. The story, Enough Rope, featured a detective named Columbo, a dogged, unpretentious cop modelled after Porfiry Petrovich, the shrewd magistrate from Dostoevsky’s Crime and Punishment who patiently hounds the killer until he snaps and confesses. The pair had just finished typing out a scene where Columbo interrogates a suspect and then leaves his apartment, but it ran a little short. If Levinson and Link had been using a modern word processor they might have added to the middle of the scene, but on a typewriter, that would mean retyping the whole thing from the start. Feeling lazy, they decided it would be simpler to have Columbo stick his head back through the door and say: “Just one more thing…”
The Collected Works of Kevin EG Perry 