Deuteronomy 19:11-13

11“But if anyone hates his neighbor, lies in wait for him, rises against him and strikes him mortally, so that he dies, and he flees to one of these cities,

12then the elders of his city shall send and bring him from there, and deliver him over to the hand of the avenger of blood, that he may die.

13Your eye shall not pity him, but you shall put away the guilt of innocent blood from Israel, that it may go well with you.