Numbers 35:22-25

22But if he thrust him suddenly without enmity, or hurled upon him anything without lying in wait, 23or with any stone, whereby a man may die, seeing him not, and cast it upon him, so that he died, and he was not his enemy, neither sought his harm; 24then the congregation shall judge between the smiter and the avenger of blood according to these ordinances; 25and the congregation shall deliver the manslayer out of the hand of the avenger of blood, and the congregation shall restore him to his city of refuge, whither he was fled: and he shall dwell therein until the death of the high priest, who was anointed with the holy oil.