Numbers 35:20-23

20If he pushes him out of hatred or, while lying in wait, hurls something at him so that he dies,

21or in enmity he strikes him with his hand so that he dies, the one who struck him shall surely be put to death. He is a murderer. The avenger of blood shall put the murderer to death when he meets him.

22‘However, if he pushes him suddenly without enmity, or throws anything at him without lying in wait,

23or uses a stone, by which a man could die, throwing it at him without seeing him, so that he dies, while he was not his enemy or seeking his harm,