- I know one thing only! I know that Arthur's dead, and you killed him!
- I did not kill Arthur.

9 seconds sound clip from the The Loved One (1965) movie soundboard.

You can hear this line at 00:56:33 in the Blu-ray version of the movie.

Quote context

[...]

- You just leave it to old Harry.

- You know something? You look great in black.

- Arthur!

- You know we're due at the Atwells' in 10 minutes!

- Oh, go on! Wreck the house! Stop it!

- I know one thing only! I know that Arthur's dead, and you killed him!

- I did not kill Arthur.

- Come in. I know who you are, young man. Just come right over here and just wait right here for a minute because my wife is a little upset. Will you wait here, please?

- Helen, that was a damn silly thing to say to me.

- Silly? Yes, yes, of course. You think everything's silly. This house is silly, I'm silly, the president is silly... And Arthur was silly.

- If you really loved Arthur as much as you say that you do...

[...]