I’ve got one I’m curious about: I don’t know if the consensus on the SDMB will be a “that’s no good” or a “well, actually…”
So: in DOUBLE EXPOSURE, Columbo’s target is a guy who has an alibi and no obvious motive; he also frames someone else, who has an obvious motive and no alibi; the killer also makes no secret of owning various large-barrel handguns, which he displays next to his trophies for pistol marksmanship. What he does make a secret of — and what Columbo spends the episode not figuring out — is that he can insert a smaller barrel in one of those, fire a shot to kill a guy, and then remove and hide that smaller barrel.
So if you check the barrels of the guns he displays — again, even though he has an alibi and no motive, and someone else has the reverse — they won’t match the bullet. And if you also search every place big enough to hide a small-caliber gun, you’ll likewise come up empty, because he’s only hidden the small barrel.
So, near the end of the episode, Columbo still honestly doesn’t know where to look; that is, he goes to the suspect’s office to look around in general — and gets cautioned by the guy with him that, hey, “wait a minute; flashing your badge to get past a guard is one thing, but this is searching without a warrant” — prompting Columbo to explain that he’s not actually searching.
And, at that, he doesn’t actually find anything.
Instead, his plan to get a clue is: to show the suspect a movie with a subliminal ad for ‘Columbo, Looking Around Your Office.’ At which point the suspect goes to that office and checks a spot too small to hide an entire gun, at which point Columbo catches him with the evidence and realizes how the killing was done, and explains to the killer about the subliminal cuts.
Caught, the killer states that Columbo never would’ve solved it without that subliminal-cut technique. Columbo says he’s right.
So, my question is: is subliminal advertising a legitimate way for an otherwise-stumped detective to solve a crime?