This was one my favorite Colombo episodes. Nimoy is a fantastic villain. His arrogance makes him truly cringey and you can tell as the episode continues Colombo starts to have a disdainful attitude toward him that will cumulates into an angry declaration from Colombo to Nimoy's face that he going to find something on him. I first saw this as a kid and thought "Whoa, I never saw Colombo pissed" A total change from being a lovable, smiling, bumbling to cold, direct, and focused. I have to admit, it was scary.
Watch it for the cat and mouse dynamics!