I finally got around to finishing the Shooting Columbo book and it got me interested in the 2 scripts that went unproduced, Shooting Script (by Brian De Palma) and Columbo's Last Case (by Peter Falk). Has anybody read either of these and are they available to read online anywhere?
Sorry, I don't know if they are publicly available, but I would note that there may be other such scripts in the wild. For example, another script by Frank D'Angeli was purchased, but never produced, which as I recall was named "Murder by Suicide." It featured Columbo's upcoming retirement, and a retirement party with other cops, who gifted him with a bowling ball.