There's one way I think the story wants you to suspect Wayne Taylor more than anyone else, because the Commodore tells everyone that Taylor is the only person he really trusts. I'm pretty sure that's a big tradition in murder mysteries, the most trusted person being the killer.
To be honest, this is one of my favorite episodes. I love the playfulness between Robert Vaughn and Columbo in all Robert's roles. You see it in Troubled Waters also. And you have to love the rivalry between Mac and Bruce Kirby aka Sgt Kramer both vying for the acceptance from Columbo.