Columbo, Season Seven

Paul Gerard:
When did you first suspect me?

Lt. Columbo:
Well, after it happened, sir, about two minutes after I met you.

Paul Gerard:
That can't be possible.

Lt. Columbo:
Oh, you made it perfectly clear, sir, the very first night when you decided to come to the restaurant directly after you were informed that Vittorio was poisoned.

Paul Gerard:
I was instructed to come here by the police.

Lt. Columbo:
And you came, sir.

Paul Gerard:
Yes.

Lt. Columbo:
After eating dinner with a man that had been poisoned. You didn't go to a doctor. You came because the police instructed you. You didn't go to a hospital. You didn't even ask to have your stomach pumped. Mr. Gerard, that's the damnedest example of good citizenship I've ever seen.