D.C. Code § 16-2303

For purposes of this subchapter, jurisdiction obtained by the Division in the case of a child shall be retained by it until the child becomes twenty-one years of age, unless jurisdiction is terminated before that time. This section does not affect the jurisdiction of other divisions of the Superior Court or of other courts over offenses committed by a person after he ceases to be a child. If a minor already under the jurisdiction of the Division is convicted in the Criminal Division or another court of a crime committed after he ceases to be a child, the Family Division may, in appropriate cases, terminate its jurisdiction.