I have also wondered how Oscar Finch could work up such an elaborate plan so quickly. I just assumed that Staplin had been threatening him for a long time and that he had already decided what to do if Stapling ever gave an ultimatum.

Regarding the gun, if the police can't find it, they can't do a ballistics test on it. I would assume with Finch being a suspect they would ask him if he had a gun and there is a registry so they would know if he ever purchased one and what type it is. So for the sake of the story, we must accept that a high-powered lawyer had an illegal gun for some reason, lol.

That's pretty classic that you saw the warrant and they put "Lt. Columbo". They could have at least spelled Finch right.

I've heard that bite marks can be used in court, but they are more controversial, since it is more common to have people with similar patterns, unlike fingerprints.

I really love this episode also. Patrick McGoohan and Peter Falk always work well together. I think McGoohan has the record for playing the most Columbo murderers. He starred in four and directed five. After him I believe is Robert Culp who was a three time killer and the very arrogant father of another. Then again, Last Salute to the Commodore may be counted as a negative episode, dropping McGoohan down to three, lol.