I believe that, in US law at least, there's such a thing as acceptable deception. As long as it is after the fact (i.e. not entrapment), this kind of thing can be used to establish lines of inquiry and/or extract admissible evidence.

We have to wonder why Mayfield would not claim this, and of course if he did, we would not have the fun of watching a seriously dislikeable character apprehended.

This episode is one of my favorites. But we have to forget reality in a number of areas. First, that the good doctor is wide awake and able to speak to a detective - only hours after open heart surgery.

The other is that the suture that Columbo takes from his surgery garb has no blood on it - at all.

So Dr. Mayfield would HAVE to say Columbo planted the suture. Even if he didn't he would be freed after ten minutes in jail - his lawyer would bring up the evidence immediatel.

Of course we are supposed to ignore the bloodless suture so it does not play into the story.

This is a very good point. And even before that, I can't understand how a team of highly skilled surgeons who had been instructed to watch Dr. Mayfield's every move would fail to see what happened to the dissolving suture that was already in Dr. Heidemann's heart.

He plants evidence in s2e4 - the ep in England. Had the individuals been innocent, they would have been convicted unfortunately because of Columbo's guesses.