Deuteronomy 19:11-13
11 But if a man hates his neighbor and lies in wait for him, assaults and kills him, and then flees to one of these cities,
12 the elders of his town shall send for him, bring him back from the city, and hand him over to the avenger of blood to die.
13 Show him no pity. You must purge from Israel the guilt of shedding innocent blood, so that it may go well with you.