Upon the request of the attorney general or a district attorney and upon a showing of probable cause under s. 968.12, a court shall issue a subpoena requiring the production of documents, as specified in s. 968.13 (2). The documents shall be returnable to the court which issued the subpoena. Motions to the court, including, but not limited to, motions to quash or limit the subpoena, shall be addressed to the court which issued the subpoena. Any person who unlawfully refuses to produce the documents may be compelled to do so as provided in ch. 785. This section does not limit or affect any other subpoena authority provided by law.