One of the clues that catches Columbo's eye in CAUTION: MURDER CAN BE HAZARDOUS TO YOUR HEALTH is the different ways the cigarettes in the ashtrays have been put out. Bud Clarke crushes them while the ones that Wade Anders planted were twisted/tapped out. While watching A DEADLY STATE OF MIND, I noticed that Dr. Collier was putting his cigarettes out by using the tapping/twisting method. It's nothing mind-blowing, just a little something that caught my eye.

Amazing observation! I love little notes like that.

Here's another one - in "Any Old Port in a Storm," Adrian Carsini murders his brother, leaves his car abandoned, and rides back on a bicycle. In "Strange Bedfellows," Graham McVeigh... murders his brother, leaves his car abandoned, and rides back on a bicycle.