reply to Mahaloth:
Is Columbo the guy from the TV show? Yes.
Are the prominent brothers real? Yes.
Have most of us heard of the brothers? Yes.
Is Fred a person and is he real? Yes.
Does this involve plagiarism? Yes.
Does this involve a random show in the TV show Columbo showing something that later was used in court? No. Note: I remember an incident where someone proved they were innocent because they were at a baseball game that happened to appear in a movie.
Did the plagiarism involve music? Written text? Art? Some other form of intellectual property, e.g. computer code?
Was something involving Columbo incorporated into the plagiarized material? Into the original source?
Did Columbo help to establish the date of either the original or the plagiarized version?
reply to Fretful_Porpentine:
Did the plagiarism involve music? No. Written text? Yes. Art? No. Some other form of intellectual property, e.g. computer code? No.
Was something involving Columbo incorporated into the plagiarized material? Yes. Into the original source? Yes.
Did Columbo help to establish the date of either the original or the plagiarized version?
No.
I’m guessing it was the copyright trap of Columbo’s first name being Philip (It was actually Frank) published in a book of facts that was plagiarized by Trivial Pursuit.
You got it Saint_Cad!
Parker Brother’s Trivial Pursuit had a question about Columbo’s real name. TP gave the wrong answer of “Philip.” The wrong answer came from Fred’s book of trivia, which had a wrong fact purposely added to prevent copyright theft. The Columbo clue proved the creators of the game had mined Fred’s trivia book in the creation of their trivia.
Here we go
Despite exploring Antarctica, serving during the Spanish-American War, Boxer Rebellion and declared missing-in-action during World War I, he never existed.
Did he go to an Ivy League school?
Nope. He didn’t
I’ll ask some Q’s that might be automatic No’s, but I want to anyway:
Is this a real human being?
Is this a female?
Is this fictional?
Is this a character from a book, movie, tv show, or something else fictional?
Have we heard of this individual?
Is it an animal?
Not a human therefore not a female.
It is fictional and from a book, however it was written in a way to make it seem authentically historical.
I cannot know who has heard of him. His identity is not a secret if that is what you mean.
It is not an animal.
Is it something with utilitarian value?
If so, would the value be primarily military?
Is it something with symbolic value, such as a flag, a scepter, someone’s good-luck charm, or whatever?
Would it be most closely associated with a single character in the book?
Yes to both
Nope
As you wrote the question: no.
Was possession of the item passed from one individual to another one or more times? That is, it was associated with more than one character, but just one at any given time?
If so:
When the item changed hands, was it an impersonal transaction, such as a sale or trade, lost in a poker game, lost and/or stolen, etc.?
Was it passed down within a family, from one generation to the next?
Was it a weapon?
I’m going to say no on this.
Is it a vehicle of some kind?
A boat or ship?
But was he here?
Kilroy wasn’t here until the end of WWII, if that’s what you’re thinking.
Hey, it all happened before I was born 
It is not Kilroy
Does “he never existed” simply mean that “he” is from a book and not real life? Or did “he” never exist within the context of the book? (I.e., talking stuffed animals exist within the fictional world of Winnie-the-Pooh, but Heffalumps and Woozles probably do not.)
Is “he” an inanimate object (within the book)? If yes – an object representing something animate, like a teddy bear or toy soldier? Would most people see “he” as an appropriate pronoun, as opposed to “it”?