Two items to address here.

1. As soon as Columbo says to Mayfield that he is finally rid of him, and leaves, if I were Mayfield, I would have immediately locked my office door (he had time to do so) and put the sutures somewhere else for disposal down the road.

2. As far as the sutures are concerned, I'm very confused about the operating room scene when he replaces the valve in Heidleman's heart for the 2nd time. Every one is watching. Yet what exactly does he do with the sutures he has removed? They don't end up on the operating table, or the suture table. We know he hid them, however, with everyone watching, someone would have seen him hiding the sutures on his person (until he mythodically pushes Columbo and transfers them). Also, the doctor standing by tells Columbo the all looked like normal, permanent sutures. That must have meant that Mayfield pulled a Santini on them, making them reappear someohow as normal sutures and place them on the tray when nobody was looking. However, this is also impossible. So I'm stumped here, two times.