I was watching "Mind over Mayhem" recently, and I discovered that I have some questions regarding the plot. Why does Dr. Cahill move the body into the house, pour glasses of wine, light his cigar, etc? He was trying to make it look like a heroin addict broke into the garage to steal the chemicals, so wouldn't it have been more sensible to move the body back into the garage where the chemicals were and where Nicholson actually had been working?

And after Cahill lights the cigar, we never see him smoking it, so he must have done that to leave a false clue, but Columbo eventually uses it against him. Does this make sense to anybody?

The only real clue we get out of the house scenario is the shoe polish smudge on the wall, but there could have been a shoe polish smudge on the garage wall instead.

I just watched this for the first time as well and I noticed a lot of plot holes like these. I'd heard it was a weak Columbo but I actually enjoyed it a lot - both Peter Falk and the guy playing the murderer are on form and there are a lot of classic elements. However, the story is weak on many different levels. As well as the points noted above, running someone over in their drive is a messy and unreliable way to kill someone (surely the coroner would have spotted how he was killed right away), plus the victim had loads of time to get out of the way. The biggest plot hole of all revolved around the victim's wife, who seems not the least bit upset about her husband's death and implausibly refuses to break patient confidentiality when Columbo shows her the missing file, which clearly implicates the son or his father. At the beginning of the story, the victim tells his murderer that he and his wife both know about the plagiarism so why aren't both murdered and why is the wife so reluctant to face up to the obvious connection between this and her husband's death? There are hints that she and the son are having an affair but Columbo's bluff at the end is done in such a way that it is never clear whether they are or not. If she was, her story would make more sense.