I also nominate for honorable mention the scene in "Now You See Him" where Columbo first walks on the scene. In his new (uncomfortable) raincoat he quickly dismisses the guests, somewhat to the Sgt's embarrassment; Then he proceeds to breakdown how Jesse Jerome could have fallen in the way he was found.

Also there is the scene in "A Stitch In Time" where Dr. Mayfield resets his desk clock as he learns of his nurse's murder. It's a short scene but when Columbo says what a terrific surgeon Mayfield must be we know that Columbo already suspects him.