Deuteronomy 19:11-13

11But perhaps somebody does hate another person. He may hide himself so that he can catch his enemy. Then he may attack him and kill him. After that, he may run to one of the safe cities.

12If he does that, the leaders of his own town must fetch him back. They must bring him to the dead person's relative. He must die as his punishment.

13Do not be sorry for him. You must punish murderers with death. Then Israel will not be guilty of evil acts. If you do that, everything will be well for you.