The punishment for a person who inadvertently kills another person is being exiled to a city of refuge. The Sages note the language of the verse that describes that halakha: “God caused it to come to his hand,” and derive that it indicates that God caused the person to inadvertently kill the victim.

“But for one who did not have intent and God caused it to come to his hand, I will provide you a place where he shall flee” (Exodus 21:13). What is the verse speaking about? It is speaking about two people who killed other people: One killed unintentionally [and should be exiled to a city of refuge], and one killed intentionally [and should be executed]; but there are no witnesses to either act, [so they will not receive their due punishments]. The Holy One, blessed be He, arranges for them to be in one inn. This one, who killed intentionally, sits beneath a ladder; and that one, who killed unintentionally, descends the ladder, and falls upon the intentional killer and kills him. That one who killed intentionally is killed, and that one who killed unintentionally is now exiled, [so ultimately each of them receives his due punishment]. (Makkot 10b)