I've seen some dummies in my time, but you're in a class by yourself.
5 seconds sound clip from the The Big Heat (1953) movie soundboard.
You can hear this line at 00:29:49.314 in the Blu-ray version of the movie.
Quote context
[...]
- It was an old-fashioned killing. Prohibition kind. That's why I thought you might...
- I don't care what you thought. I'm glad to help you boys whenever I can.
- But I got an office for that sort of thing. This is my home. And I don't like dirt tracked into it.
- I see. And I violated your immaculate home, is that it?
- That's exactly it. And tomorrow morning, I'll see you don't get the chance to do it again.
- What'll you do... make another phone call, or have somebody make it for you?
- I've seen some dummies in my time, but you're in a class by yourself.
- I'm stupid because I want some answers about a murder. Is that it?
[...]