Not to discount Miss Piggy's homicidal abilities, but I was thinking in terms of actors of some ability-- who on the surface we wouldn't think of as Columbo villains--but may have the talent to pull it off. Carl Reiner? Ray Ramono? Kelsy Grammer, mentioned earlier, would be fantastic, but what about Niles?
No one could ever discount Miss Piggy!! And she may have a few words to say to you Michael about her acting abilities!!!
But if I could think of some "real" person who would be an unlikely murderer....how about James Garner....or Bill Cosby...or Tony Danza...Alan Alda...or Doris Day...???
And to take this a step further.....wouldn't it have been great to see the wonderful Vito Scotti as a guest murderer!!....oh the fun he and Peter would have had filming that one!!
Cassa, with Vito Scotti as the guest murderer, now that's the one I wouldn't mind sitting in on! Say, how about Tom Hanks, Billy Crystal, Danial Stern, Jack Palance and Joe Pesci?.