I'm sure that you've debated this topic before, nevertheless...

Some of the murderers in the Columbo series stick out as very poor murderers/murderesses:

1. Roger Stanford - Roddy McDowall (Short Fuse): the script-writer gives neither him nor the viewer any sort of substance: he does very little to "cover his tracks" and seems to incriminate himself at every turn. Sloppy with considerably mis-placed confidence to boot!

2. Viveca Scott - Vera Miles (Lovely But Lethal): as well as suffering from bland characterisation, this murderess lets her infection caused by the poison ivy become too obvious an irritation to Columbo.

3. (This will cause some argument!) Dr. Eric Mason - Nicol Williamson (How to Dial a murder): ingenious means of committing the murder, but thereafter he too leaves his motive and opportunity significantly exposed. As Columbo says at the end - "I found you disappointing...you left enough clues to sink a ship!".

4. Oliver Brandt - Theodore Bikel (The Bye-Bye Sky High I.Q. Murder case). An intellect with very little backbone or common sense. His "creative bookkeeping" was not particularly well-concealed and it would have been better just to have "buttered up" his partner and friend Bertie, who, at one point, says that he could never have hurt Oliver. Brandt is never really comfortable once the murder is committed.

What do other people think?

Sorry - my typing is not up to scratch..again - the subject should read as above.

Leighton

It seems logical to include Ruth Lytton (Joyce Van Patten, "Old Fashioned Murder") among the weakest adversaries of the series. She did not seem to quite know what she wanted to do as the case progressed.

I think Roddy McDowall gave a great performance, but yes, Roger did not plot out his ability to cover his tracks well since his scheme in effect depended on being sure that his aunt would never want to speak again to William Windom and Anne Francis respectively to hear their side of the story, which would have resulted in Roger being exposed right away.

My top vote for a weak one would have to be Swanny Swanson from Last Salute to the Commodore....he was pretty lame....a real wimp...and here he was a middle-aged man still getting an "allowance" from his uncle...pretty sad.

I agree that Swsnny Swanson was a weak adversary in Columbo. WHo gets an allowance from his uncle when he is a middle age man. Can't he inherit his money already or what

I always thought that for as smart as he was, Nelson Brenner ("Identity Crisis") was unbelievably stupid in meeting Geronimo at the amusement park where they were seen and photographed together. It is true that Geronimo mentioned that Brenner thought that it was actually better to meet at a public place, but it sured backfired. Also, when Columbo first meets him and he keeps saying "you have the wrong room" for no apparent reason, it is sure to draw attention to himself.

Also, Alex Benedict ("Etude in Black") was really stupid for two reasons: (1)in insisting that Jennifer Wells "had to have committed suicide". As someone who was supposedly uninvolved, when Columbo said he thought it was murder he should have acted shocked and said "you had better find this despicable person who did this!". It sounds very strange for him to insist that it was suicide since he had no direct interest in the case.
(2) picking up the flower in such an obvious way in front of Columbo was dumb also. Why didn't he just stick it in his pocket?

I think Alex benedict thought that no one was looking and he could of put on the carnation on his lapel but Columbo was there and as usual he was snooping around

If the action was good enough to repeat in "Matlock: Diary of a Perfect Murder" years later, it could not have been so stupid. What is the big difference between a carnation and a name tag anyway?

YM..I agree that Nelson Brenner and Alex Benedict come off as terrifically inept and stupid. Your reasons are valid. But in both those cases I have always chalked it up to the fact that they were just so overly confident that they would never get caught. Brenner had the "agency" to protect him, and Alex was just a cocky son-of-a-gun!

When "stuff" like that happens I attribute it to the murderers being first-timers. Remember that great speech Columbo has in Prescription: Murder when he says that even though a murderer may be brilliant, he has just one chance; but cops have done investigations hundreds or thousands of times?