I just chose an episode at random, it is shitty ... and some guy reviewing it at IMDb says so!! I really know how to pick 'em!
https://www.imdb.com/title/tt0641586/
A Total Clunker
Whether poorly written, miscast, or misdirected, this episode fell short of expectations by miles. Where to begin?
The premise is fine; a crime takes place in full view of credible witnesses who have no idea a crime is being committed. Pretty cool, but it simply goes nowhere after that. I'll ask: If you were part of the operation that pulled a job, would you allow a private detective to snoop around, let alone show him one of the ways you did it? Of course not, but one of the perps did. Also, Mannix isn't the Joe we know, either. He's simply not on his game, even though he impossibly found a way in to the crooks' lair. Additionally, one of the victims of the crime is far too unbelievable to be taken seriously. It's what I mean about the writing, casting, and direction.
If you skip this episode, you won't miss it.