D.C. Code § 34-918
Each of the commissioners and every agent provided for in § 34-906, for the purposes mentioned in this subtitle, shall have power to administer oaths, certify to official acts, issue subpoenas, compel the attendance of witnesses and the production of books, accounts, papers, records, documents, and testimony. In case of disobedience on the part of any person or persons to comply with any order of the Commission or any commissioner, or any subpoena, or on the refusal of any witness to testify to any matter regarding which he may be interrogated before the Commission or its agent authorized, it shall be the duty of the Superior Court of the District of Columbia, or a judge thereof, on application of a commissioner, to compel obedience by attachment proceedings for contempt, as in the case of disobedience of the requirements of a subpoena issued from such court or a refusal to testify therein.
D.C. Code § 34-918