Deuteronomy 19:11-13

11“But suppose someone is hostile toward a neighbor and deliberately ambushes and murders him and then flees to one of the cities of refuge.

12In that case, the elders of the murderer’s hometown must send agents to the city of refuge to bring him back and hand him over to the dead person’s avenger to be put to death.

13Do not feel sorry for that murderer! Purge from Israel the guilt of murdering innocent people; then all will go well with you.