How Columbo's Writers Came Up With The Detective's Catchphrase

There are quite a few memorable things about the classic television detective Columbo that set him apart from the average TV cop. From his disheveled appearance and trademark tan overcoat to his perpetually lit cigar, Peter Falk's Lieutenant Columbo is clearly cut from a different, less rigid cloth. He regularly takes the rich and powerful down a few notches and always catches the murderer through a combination of attention to detail and a willingness to be a bit annoying, and it's through the latter that he uses his most famous catchphrase: "One more thing." While he doesn't always exactly say "one more thing," he uses some variation of it to let the killer know that he's caught onto them, asking some vital final question or pointing out their fatal flaw. It's one of the elements of the character that is most often referenced and parodied (besides Falk's perfect performance, which no other actor really could have done), but it wasn't ever really meant to be an important part of the character at all. 

In the book "The Columbo Phile: A Casebook," (via MeTV), writer Richard Levinson, who co-created "Columbo" with his frequent collaborator and co-writer William Link, revealed that Columbo's signature catchphrase was as casual an addition as humanly possible. In fact, you might even call it a little bit lazy. 

"Columbo" was originally a feature-length theatrical performance called "Prescription: Murder," written by Levinson and Link, which would serve as the foundation for the long-running NBC series. In the original play, Columbo wasn't quite as laid-back as he would one day become, but the writers' own casual decisions had a major impact. There was a scene they had written where Columbo had already headed offstage, but the scene felt much too short. They wrote down simply "just one more thing" onto the dialogue, intending to go back and add something more substantial later. That never happened, as Levinson explained: 

"We were too lazy to retype the scene. So we had him come back and say, 'Oh, just one more thing ...' It was never planned."

The first season of "Columbo" is honestly pretty incredible, featuring an episode directed by an early-career Steven Spielberg, but it's clear that they were making up some of the character and canon as they went along. Some inconsistencies along the way (especially with regards to Mrs. Columbo) make Levinson's story feel pretty believable. It seems that the writers and the detective were both flying by the seat of their pants, and honestly? It makes "Columbo" that much more charming.