Leviticus 5:3, 6, 17

Or if he touches human uncleanness, of whatever sort his uncleanness may be with which he becomes unclean, and it is hidden from him, and then he comes to know it, he will be guilty.

He shall also bring his guilt offering to the LORD for his sin which he has committed, a female from the flock, a lamb or a goat as a sin offering. So the priest shall make atonement on his behalf for his sin.

“Now if a person sins and does any of the things which the LORD has commanded not to be done, though he was unaware, still he is guilty and shall bear his punishment.