Leslie Williams was worse than Kay - she was fueled by greed and completely used and killed a man that loved her.

Dr. Mayfield was worse, for trying to kill a man that was nothing but good to him, and then taking out more innocent bystanders.

I find Ken and Riley hard to differentiate because they were played by the same person, similar industries, and both characters were greedy and arrogant. If I had to choose one though, I guess it would be Ken Franklin, because he killed such a sweet guy that had, for whatever reason, let Ken take all the glory for work he had never really done - so he should have been forever grateful to him, and just retired and collected royalties.

From everything that Columbo learned about Ken's lifestyle, that insurance money would've been gone in no time anyway. So along with the nastiness of it, it was a complete WASTE.

Thanks for this study in character. I appreciated it.