After It's All in the Game (1993), this is the second time that someone asks Columbo for his first name and he replies "Lieutenant."
This episode is an adaptation of the 1970 novel "Jigsaw" by Evan Hunter (otherwise known as Ed McBain). After No Time to Die (1992), this is the second episode of the series to be adapted from one of his 87th Precinct novels.
This is one of the very few times that Columbo carries a gun. He aims it at a man but doesn't fire.