Numbers 35:29-32

29Wherever you and your descendants live, these are the rules that you must obey for all future time.

30Before you kill a murderer, people must agree that they saw him kill someone. But if only one person saw what happened, that is not enough for you to kill him.

31You must not accept money to pay for the life of a murderer. If he is guilty of murder, you must kill him.

32Also, you must not accept money from a killer who has run to a safe city. You must not let him return to his own home until the leader of the priests has died.