- You found it. You could've known about it all the time.
- But I didn't.

3 seconds sound clip from the Clue (1985) movie soundboard.

You can hear this line at 01:11:58.712 in the Blu-ray version of the movie.

Quote context

[...]

- How could he risk it? We might've seen him running back.

- Not if they used this secret passage.

- And the murdered ran back down the secret passage to the study.

- That's where it comes out?

- Yes! Look!

- What?

- How did you know?

- This house belongs to a friend of mine. I've known all along.

- So you could be the murderer.

- Don't be ridiculous. If I was the murderer, would I reveal to you how I did it?

- Well, who else knew about the secret passage?

- We found it, Colonel Mustard and me.

- You found it. You could've known about it all the time.

- But I didn't.

- Well, why should we believe you?

- Because she was with us all in the billiard room doorway while Yvette was screaming, don't you remember?

- But what I don't understand is why was the cook murdered? She had nothing to do with Mr. Boddy.

- Of course she did.

- I gathered you all here together because you were all implicated in Mr. Boddy's dastardly blackmail.

[...]