Leviticus 5:1-3

1“When someone sins in any of these ways: If he has seen, heard, or known about something he has witnessed, and did not respond to a public call to testify, he will bear his iniquity.

2Or if someone touches anything unclean  — a carcass of an unclean wild animal, or unclean livestock, or an unclean swarming creature  — without being aware of it, he is unclean and incurs guilt.

3Or if he touches human uncleanness  — any uncleanness by which one can become defiled  — without being aware of it, but later recognizes it, he incurs guilt.