Maryland Code, Labor and Employment § 3-408

(b)(1) In an investigation under this subtitle, the Commissioner shall try to negotiate with an employer to obtain the testimony or documentary evidence that is needed to determine whether a violation exists.

(2) If the Commissioner is unable to obtain evidence by negotiation, the Commissioner may issue a subpoena for the attendance of a witness to testify or the production of documentary evidence that relates to the subject matter of the complaint.

(3) Each application for a subpoena under this subsection shall:

(4) A subpoena may not be issued unless the application is approved by the Attorney General as to form and substance.

(5) If a person fails to comply with a subpoena issued under this subsection, on a complaint filed by the Commissioner, a circuit court may compel compliance with the subpoena.