i'll do a couple fred...
gene and ruth's son was named robbie. the only reason i know this is that there is a guy who posts on this site who is named robbie.
the cleaning of the fingerprints off the gun, but not the bullets was from fade in to murder....a rather lackluster ending to an otherwise terrific episode.
rosebud....(way too easy fred!) how to dial a murder.
david...i know what it is...and it is one of my favourite episodes....no! not THAT one....but i like this one a lot.
but i can't say what it is because i was looking at my columbo phile book the other day and i noticed it. so if i said the answer it would be basically cheating.