When the magician demonstrates the guillotine to Columbo for the first time, he has Columbo lay down on the bench and he puts the wooden collar over his neck. He then lowers the inside track from horizontal ("safe" position) to perpendicular so the blade can come down. After the blade drops he removes the collar, but the track is back in the horizontal position without him putting it back to "safe".
Around the 42-minute mark, Blake asks Columbo to pick a shape and draw it; Blake proceeds to guess the shape Columbo drew by "reading his mind". Later, Columbo pulls the same trick on Blake, but Blake isn't able to discern how it's done.
While not ideal, a Phillips head screw sometimes can be screwed by a "regular" flat-bladed screwdriver, but not vice versa. To make the screwdriver plot more believable, the types of screwdriver should have been reversed.
Two actors are credited as "Magician at Cemetary", but there is a misspelling. There is no "A" in Cemetery.
Max raises the hoistway door of the freight elevator before he sends it down. There are safeties that don't allow an elevator to run when the hoistway door is open because leaving an opening into a hoistway is dangerous.
Columbo does some research on the psychic and says he read the psychic's "curricular vitae." The correct term is "curriculum vitae."
When Colombo is asked by Tommy to pick a card, he picks the ace of diamonds; the boy has him replace the card in the middle of the deck and then shows Columbo that the card is on top. Then, the boy accidentally shows the camera that all the cards in the deck are aces of diamonds as he walks away. However, this was intentional so that the viewer would be let in on how the trick was done.
When Columbo is called to a bar in the beginning, the police officer says to Columbo that the manager won't speak to anyone but homicide. No reason is given for this, and the reason for making the call was blood dripping from the ceiling. There is really no reason to not just report this directly to the police, who will report this to homicide. His secrecy was never questioned and makes no sense.
However, the manager was a former policeman and was familiar with the tenet being a member of the magic club. His police "intuition" likely led him to the conclusion that the police homicide department was needed.
However, the manager was a former policeman and was familiar with the tenet being a member of the magic club. His police "intuition" likely led him to the conclusion that the police homicide department was needed.
Columbo starts moving things at the crime scene before photographs have been taken.