That sounds like a confession to me. In fact, the double negative has led to proof positive. I'm afraid you gave yourself away.
5 seconds sound clip from the Clue (1985) movie soundboard.
You can hear this line at 00:21:32.203 in the Blu-ray version of the movie.
Quote context
[...]
- Not me.
- You're not being blackmailed?
- I'm being blackmailed all right. But I did what I'm being blackmailed for.
- Yeah? What's the phone number?
- So how did you know Colonel Mustard works in Washington? Is he one of your clients?
- Well, you tell them it's not true.
- Aha! So it is true! A double negative.
- A double negative? Do you mean you have photographs?
- Are you trying to make me look stupid in front of the other guests?
- You don't need any help from me, sir.
- But he holds a sensitive security post in the Pentagon.
- And, Colonel, you drive a very expensive car for someone who lives on a colonel's pay.
- I don't. I came into money during the war when I lost my mommy and daddy.
[...]