Just watching Exercise in Fatality – in the tense hospital waiting-room scene, while Columbo argues with Milo Janus, the painting directly behind his head clearly shows the artist’s signature: Sam Franklin (Suitable for Framing) – looks like Dale Kingston’s review really ignited his career after all!

I noticed that also.

I forgot to mention that in the episode, "The Most Crucial Game," Columbo goes over to Eric Wagner's house, to talk to Paul Hanlon. In the background there is music playing on the stereo system. It is the music that was featured in "Etude in Black." This is where Columbo discovers the house was bugged.