Lev 5:2-3

2Or when any of you touch any unclean thing—whether the carcass of an unclean beast or the carcass of unclean livestock or the carcass of an unclean swarming thing—and are unaware of it, you have become unclean, and are guilty.3Or when you touch human uncleanness—any uncleanness by which one can become unclean—and are unaware of it, when you come to know it, you shall be guilty.