I think the most feeble ‘gotcha’ Columbo ever used, which makes the knot-tying gotcha seem like DNA evidence in comparison, is one where the murderer leaving the scene of the murder passed a blind man, the only ‘eyewitness’.
At the big gotcha reveal, Columbo tells the murderer they’ve found an eyewitness, and brings in a man wearing dark glasses, who appears to be the blind man. The murderer says, preposterous! You obviously coached him to be able to walk to the couch and sit down on his own, thus appearing sighted, but this man is clearly blind! Columbo says, how can you tell? The murderer says, I’m a doctor! I can tell by the cast of his eyes, his movements, etc.
Then Columbo makes the big reveal- he hands the ‘blind’ man a newspaper. He can read it! He can see! It turns out the man is the actual blind man’s brother, who somewhat resembles him (I don’t think he was an identical twin). Columbo says 'there’s no way you’d assume this witness was blind unless you had been there to see the actual blind brother pass you as you walked away from the murder site!" Off to jail.
The thing is, blind or not, the man walked in the room wearing dark glasses indoors. Anybody might just assume he’s blind.