The murderer crept up behind him and killed him!
4 seconds sound clip from the Clue (1985) movie soundboard.
You can hear this line at 01:14:28.831 in the Blu-ray version of the movie.
Quote context
[...]
- One of us slipped through the same secret passage.
- Again?
- Of course. Back to the study.
- The murderer was in the secret passage.
- Meanwhile, Mr. Boddy had been on the floor. He jumped up.
- The murderer came out of the secret panel, picked up the candlestick.
- Mr. Boddy followed us out of the study and into the hall looking for an escape.
- The murderer crept up behind him and killed him!
- No.
- So who wasn't there the entire time in the kitchen?
- Whoever it was is the murderer.
- And we put the weapons in the cupboard locked it, and ran to the front door to throw away the key.
[...]