It's one of the standard plot points of a Columbo mystery that either the clue which points him to the murderer in the first place, or the final clue which gives Columbo the evidence he needs to set up a final confrontation with the murderer leading to an arrest, is some minor thing out of place or unusual about the murder scene.
In this one, the clue we knew was going to trip up the murderer was a mysterious itch on the hands of both the murderer and Columbo. They focused on it so much we were obviously supposed to notice it, and it indeed turned out to be related to the final clue: That both had come into contact with urushiol, the irritant in poison ivy, and this could have happened from contact with nothing else but either something at the murder scene or the missing MacGuffin because poison ivy doesn't grow in Southern California.
However, a different plant from the same family, poison oak, not only DOES grows in Southern California, but can be difficult to avoid anywhere wild plants grow. (Urban residents often don't recognize it when they see it.) And the dermatitis you get from poison ivy and poison oak are absolutely indistinguishable -- as you would expect, since it's caused by exactly the same chemical. When Columbo sees an expert about his itch, he's told it can only be poison ivy. But no one in Southern California would even begin to suspect poison ivy. They'd say it was poison oak, period.
It's a nonsense clue, and a horrible failure by the writer to do even remotely adequate research.
If there was much comedy to this episode or if the acting were amazingly good it might be possible to overlook this issue, but unfortunately neither were the case. The result is well below average for Columbo.
In this one, the clue we knew was going to trip up the murderer was a mysterious itch on the hands of both the murderer and Columbo. They focused on it so much we were obviously supposed to notice it, and it indeed turned out to be related to the final clue: That both had come into contact with urushiol, the irritant in poison ivy, and this could have happened from contact with nothing else but either something at the murder scene or the missing MacGuffin because poison ivy doesn't grow in Southern California.
However, a different plant from the same family, poison oak, not only DOES grows in Southern California, but can be difficult to avoid anywhere wild plants grow. (Urban residents often don't recognize it when they see it.) And the dermatitis you get from poison ivy and poison oak are absolutely indistinguishable -- as you would expect, since it's caused by exactly the same chemical. When Columbo sees an expert about his itch, he's told it can only be poison ivy. But no one in Southern California would even begin to suspect poison ivy. They'd say it was poison oak, period.
It's a nonsense clue, and a horrible failure by the writer to do even remotely adequate research.
If there was much comedy to this episode or if the acting were amazingly good it might be possible to overlook this issue, but unfortunately neither were the case. The result is well below average for Columbo.