Numbers 35:20-23

20“If anyone pushes someone maliciously, or throws anything at him with deadly intent,

21or with hostility hits him with his fist so that he dies, the one hitting him is a murderer. The blood avenger may put the murderer to death when he finds him.

22But if he pushes him suddenly or throws an object at him with no intent,

23or without seeing him should drop a stone on him resulting in his death, but he was not his enemy and intended him no harm,