Proverbs 28:17

A man that doeth violence to the blood of any person shall flee to the pit; let no man stay him.
– Proverbs 28:17

The word for violence is a form of the same word in translated oppressor in verse 16. It typically refers to extortion, and here is coupled with blood, so it refers to murder. Fleeing to the pit refers to going to the grave and means that guilt overwhelms the murderer. The last line is difficult and has been interpreted variously. It most likely seems to be a warning against interfering with justice.