Numbers 35:19-25

19The blood avenger himself shall put the murderer to death; he himself shall put him to death when he meets him. 20Now 1if he pushed him in hatred, or he threw something at him 23with malicious intent, and as a result he died, 21or if he struck him with his hand with hostility, and as a result he died, the one who struck him must be put to death; he is a murderer. The blood avenger shall put the murderer to death when he meets him.

22‘4But if he pushed him suddenly, without hostility, or threw any object at him without 5malicious intent, 23or had any 6deadly stone, and without looking he dropped it on him so that he died, while he was not his enemy nor was he seeking 7to harm him, 24then 8the congregation shall judge between the one who fatally struck the victim and the blood avenger in accordance with these ordinances. 25And the congregation shall save the one who committed manslaughter from the hand of the blood avenger, and the congregation shall return 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.