Numbers 35:19-25

19The blood avenger himself shall put the murderer to death; he shall put him to death when he meets him. 201If he pushed him of hatred, or threw something at him 2lying in wait and as a result he died, 21or if he struck him down with his hand in enmity, and as a result he died, the one who struck him shall surely be put to death, he is a murderer; the blood avenger shall put the murderer to death when he meets him.

22‘3But if he pushed him suddenly without enmity, or threw something at him without lying in wait, 23or with any 4deadly object of stone, and without seeing it dropped on him so that he died, while he was not his enemy nor seeking his injury, 24then 5the congregation shall judge between the slayer and the blood avenger according to these ordinances. 25The congregation shall deliver the manslayer from the hand of the blood avenger, and the congregation shall restore him to his city of refuge to which he fled; and he shall live in it until the death of the high priest who was anointed with the holy oil.