Wis. Stat. § 946.60: Destruction of documents subject to subpoena.

(1) Whoever intentionally destroys, alters, mutilates, conceals, removes, withholds or transfers possession of a document, knowing that the document has been subpoenaed by a court or by or at the request of a district attorney or the attorney general, is guilty of a Class I felony.

(2) Whoever uses force, threat, intimidation or deception, with intent to cause or induce another person to destroy, alter, mutilate, conceal, remove, withhold or transfer possession of a subpoenaed document, knowing that the document has been subpoenaed by a court or by or at the request of a district attorney or the attorney general, is guilty of a Class I felony.

(3) It is not a defense to a prosecution under this section that:

(a) The document would have been legally privileged or inadmissible in evidence.

(b) The subpoena was directed to a person other than the defendant.