Watching this today and recalled the clever technique of splitting the screen to show the different scenarios and events unfold. I liked this but notice it was never used in other Columbo films,or was it?

It was used in Death Lends a Hand. the audience is viewing things - as I recall - from Brimmers glasses. k

Not always split screen, but there are several episodes where the camera work is very creative.

Fred mentioned the view with Brimmer's glasses.

Other artistic uses of camera and audio include the creepy, circus-like, kaleidoscopic sequence at the editing board when Columbo is closing in on Kay Freestone in "Make Me a Perfect Murder."

The freezing of Lily LaSanka's scream always grabbed me, as well as the click clack of the typewriter at the opening of "Murder by the Book." All worthy of Steven Spielberg.

I remember as a kid being disturbed by the scene from the point of view of the friend of Sharon Martin as he falls down the stairs, drugged by Dr. Mayfield.

I'm sure there are others I'm not remembering right now.

The device of the murderer 'imagining' the plot is also used in 'The Most Dangerous Match'. This scene is deleted from the DVD version though (at least in the UK version).

Yes, the creepy chess match with human pieces, right before his own "chess match" with Columbo.

Great example.