First name
The signature of Lt. Frank ColumboColumbo's first name was never spoken aloud in the series. However, recent DVD releases reveal that his first name may be shown on an ID badge he carries.
Several sources cite the lieutenant's name as "Philip Columbo", variously claiming that the name was either in the original script for Prescription: Murder or that it was visible on his police badge. For instance: "A rumour that Columbo's first name -- which is never mentioned by him on screen -- is actually Peter has been denied by the star: if he has a name at all, says Falk, it is Philip, which was the name used in the original story, Prescription Murder.[1] Peugeot even ran an advertising campaign that mentioned "Lt. Philip Columbo" as the most famous driver of the Peugeot 403 convertible.
The name "Philip Columbo" was, in fact, invented by Fred L. Worth, author of The Trivia Encyclopedia, who planted the fictitious entry about Columbo's first name in his book (and its sequels) in an attempt to catch anyone who might try to violate his copyright. Worth's ploy was, however, only partially successful.
In 1984, Worth filed a $300 million lawsuit against the distributors of the board game Trivial Pursuit, claiming that they had sourced their questions from his book, even to the point of reproducing misprints and typographical errors. The ace up his sleeve was "Philip Columbo" which had appeared in a game question about Lt. Columbo, despite the name 'Philip' being an invention of Worth's.
The makers of Trivial Pursuit did not deny that they sourced material from Worth's book, but argued that there was nothing improper about using that book simply as one of the many sources from which the game's material originated. The judge agreed, ruling in favor of Trivial Pursuit and the case was thrown out of court.