It was I who killed lord Shi and Wei Chung as well!
5 seconds sound clip from the Spiritual Kung Fu (1978) movie soundboard.
You can hear this line at 01:28:45 in the DVD version of the movie.
Quote context
[...]
- And so you went and changed your name and became a junior monk in this temple.
- And so that the name of the Luk family would be known to all men.
- Soon when the book was stolen, I had my suspicions.
- It was I who killed lord Shi and Wei Chung as well!
- He had to die to make way for my son.
- But you were below in the cellar.
- Ha! There's a tunnel there you don't know about.
[...]