'Ransom For a Dead Man' is one of only two original episodes that I don't have, and I'm also not very familiar with 'Murder, Smoke and Shadows', so I cannot comment on them, but as for the other episodes you mention, the only connection I can come up with is that the killer moves the body to another location in all of them. There is probably something else I am missing though. Are these the only ep's in which the body is moved? Can't think of any others off hand. Good question, David.
I thought moving the body was the answer too, or that perhaps the body was moved using a car. But then I realized the Body Was also moved in the original series in the episodes Dead Weight, Double Shock, Any Old Port in a Storm (By Car), A Friend in Deed, An Exercise in Fatality.
For the moment, I'm otherwise stumped on this one myself.
Gregg and Rex came the closest to the answer. In all six episodes, the dead body is transported by means of the killer's car. That is why "Any Old Port in a Storm" is not included. Ric Carsini's body was transported in his own car.
If "Uneasy Lies the Crown" ought to be included on this list, please correct me. I do not remember whether the body of Adam Evans was transported in the car of Wesley Corman or David Sherwin.
David, I thought including "Dagger" was very creative of you. While Sir Roger wasn't actually in the trunk of Nicky's little roadster, he was still inside a trunk which was tied to the car!