I have three famous victims:

"Greenhouse Jungle" - Bradford Dillman

"The Most Crucial Game" - Dean Stockwell (he was a child actor and continued his prominence as he got older.)

"Identity Crisis" - Leslie Nielsen

After Fred Draper, I think the next least famous murderer was Michael McGuire who played Hugh Caldwell in "A Friend in Deed".

Another "character actor", he worked more than Draper, and had at least one memorable role as Sumner Sloan in "Cheers". He appeared in the very first episode as Diane's fiance, who dumped her and left her at the bar. He had a couple of other appearances as Sloan in the series.

This is more of a question than an answer, but I always wonder how big Clive Reville has ever been in THIS country, as opposed to Britain. I know he's familiar to people in the character actor sense, but I'm not sure about any other.

Other than Columbo, the only other thing I know I've seen Clive Revill in is The Legend of Hell House. Apparently, I've seen him in The Empire Strikes Back, Robin Hood: Men in Tights, Transformers the Movie and Zorro, The Gay Blade and never realised he was in those films.