Leviticus 5:3, 6, 17

or if he touches human uncleanness, of whatever sort the uncleanness may be with which one becomes unclean, and it is hidden from him, when he comes to know it, and realizes his guilt

he shall bring to the LORD as his compensation for the sin that he has committed, a female from the flock, a lamb or a goat, for a sin offering. And the priest shall make atonement for him for his sin.

“If anyone sins, doing any of the things that by the LORD’s commandments ought not to be done, though he did not know it, then realizes his guilt, he shall bear his iniquity.