D.C. Code § 49-502

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.