Leviticus 5:1, 6

‘Now if a person sins after he hears a public order to testify when he is a witness, whether he has seen or otherwise known, if he does not tell it, then he will bear his punishment.

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.