Leviticus 5
1 Ref And if anyone does wrong by saying nothing when he is put under oath as a witness of something he has seen or had knowledge of, then he will be responsible:
2 Ref If anyone becomes unclean through touching unconsciously some unclean thing, such as the dead body of an unclean beast or of unclean cattle or of any unclean animal which goes flat on the earth, he will be responsible: