The military courts of the District of Columbia shall be: General courts-martial, special courts-martial, the summary courts-martial, and courts of inquiry, as now or hereafter provided by law.

Courts of inquiry, to consist of not more than 3 officers, may be ordered by the Commanding General for the purpose of investigating the conduct of any officer, either at his own request or on complaint or charge of conduct unbecoming an officer. Such court of inquiry shall report the evidence adduced, a statement of facts, and an opinion thereon, when required, to the Commanding General, who may, in his discretion, thereupon order a court-martial for the trial of the officer whose conduct has been inquired into.

General courts-martial for the trial of commissioned officers or enlisted men shall be ordered by the President of the United States or Commanding General at such times as the interests of the service may require.

The constitution and jurisdiction of military courts, the form and manner in which their proceedings shall be conducted and reported, and the forms of oaths and affirmations taken in the administration of military law by such courts, the limits of punishment and the proceedings in revision shall be governed by the Articles of War and the law and procedure of the military courts of the United States.

No action or proceeding shall be prosecuted or maintained against a member of a military court, or officer or person acting under its authority or reviewing its proceedings on account of the approval or imposition or execution of any sentence, or the imposition or collection of fine or penalty, or the execution of any warrant, writ, execution, process, or mandate of the military court, nor shall any officer or enlisted man be liable to civil or criminal prosecution for any act done while in the discharge of his military duty.

The jurisdiction of the courts and boards established by this title shall be presumed, and the burden of proof shall rest on any person to oust such courts or boards of jurisdiction in any action or proceedings.

Every person not belonging to the National Guard of the District of Columbia who, being duly subpoenaed to appear as a witness before the military courts herein provided for, willfully neglects or refuses to appear, or refuses to qualify as a witness or to testify or produce documentary evidence which such person may have been legally subpoenaed to produce, shall be guilty of a misdemeanor, for which such person shall be punished on information in the criminal courts of the District of Columbia, and it shall be the duty of the United States Attorney for the District of Columbia, on certification of the facts to him by any military court herein provided for, to file an information against and prosecute the person so offending and the punishment of such person on conviction shall be by a fine of not more than $100, or imprisonment not exceeding 30 days, or both, at the discretion of the court; provided, that this section shall not apply to persons residing beyond the limits of the District of Columbia, and that the fees of such witness and his mileage at the rate provided for witnesses in the United States District Court in said District shall be duly paid or tendered said witness; and provided, that no witness shall be compelled to incriminate himself or to answer any questions which may tend to criminate or degrade him.

The sentences of said courts, whether of fine or imprisonment, shall be executed by the United States Marshal for the District of Columbia in the same manner as are sentences of the criminal courts of said District.

Whenever it shall appear to a regularly constituted court-martial convened under the provisions of this chapter that the accused, having been duly ordered or summoned to appear before such court-martial for trial, has refused or neglected so to appear, such court-martial shall issue a warrant or attachment for the arrest of the accused, directed to the United States Marshal for the District of Columbia, who shall forthwith execute said warrant or attachment, make proper return thereof to such court-martial, and produce to such court-martial the body of the accused, if within the District of Columbia, and to retain the custody thereof and continue so to produce said body during the sessions of such court-martial until the conclusion of the trial, unless sooner discharged by said court-martial.