942.05
942.05 Opening letters. Whoever does either of the following is guilty of a Class A misdemeanor:

942.05(1)
(1) Knowing that he or she does not have the consent of either the sender or the addressee, intentionally opens any sealed letter or package addressed to another; or

942.05(2)
(2) Knowing that a sealed letter or package has been opened without the consent of either the sender or addressee, intentionally publishes any of the contents thereof.