Thanks for your replies. :)

In "A trace of murder", when the killer pushes the cream and sugar toward the woman. Columbo is so stunned he has to excuse himself and regain his composure in the men's room.

And Columbo is standing in the restroom and he thinks, in his best Yuban commercial voice, "Shera *never* takes cream and sugar in her coffee at home."

(Sorry, couldn't resist!)

I was visiting a relation some years back and they had that episode on the TV but the sound was turned down. I couldn't resist glancing at the TV from time to time and I saw that scene and I reacted to it bit like Columbo did! I hadn't seen that episode before.

I find that the thing which almost always intrigues Columbo initially is the murderer's apparently cast iron alibi which usually goes along with the idea that "it could have been anybody", except the actual murderer.