Md. Code, Public Safety § 13A–712

A person not subject to this title may be punished by a State court of competent jurisdiction if the person:

(1) has been duly subpoenaed to appear as a witness or to produce books and records before a court–martial or court of inquiry, or before any military or civil officer designated to take a deposition to be read in evidence before such a court;

(2) has been duly paid or tendered the fees and mileage of a witness at the rates allowed to witnesses attending a criminal court of the State; and

(3) willfully neglects or refuses to appear, or refuses to qualify as a witness or to testify or to produce any evidence that the person may have been legally subpoenaed to produce.