D.C. Code § 47-1313
Before any such action shall be instituted, the Mayor shall cause notice to be given in the name appearing upon the records of the Assessor as the owner of such property, by registered mail or by certified mail directed to the last-known address of such person, and by publication once a week for 3 successive weeks in some daily newspaper published and circulated generally in the District of Columbia, against said person and "all other persons having or claiming to have any right, title, or interest in or to the real estate proposed to be proceeded against, their heirs, devisees, executors, administrators, and assigns," by such designation, to appear before him on a day certain, which day shall be at least 10 days after the last publication of said notice, and show cause, if any they have, why the said real estate should not be proceeded against. For the purpose of the proceedings herein provided for, the person appearing by the Assessor's records, at the time of the first publication of notice, as the owner of such property, and any other persons who may appear in response to the publication aforesaid and claim to have an interest in such property, shall be deemed proper parties defendant in any such proceedings. Upon the filing of the petition aforesaid, the Court shall enter an order directed to the person or persons named as defendants therein and "to all other persons having or claiming to have any right, title, or interest in the real estate proposed to be sold, their heirs, devisees, executors, administrators, and assigns," by such designation, directing them to appear on a day certain, which day shall be not less than 30 days after the date of the last publication of said order, and show cause, if any they have, why said real estate should not be proceeded against and sold. The said order shall be published once a week for 3 successive weeks in some daily newspaper published and circulated generally in the District of Columbia, and such publication shall be considered as sufficient service upon such person or persons as cannot be found by the Marshal within the District of Columbia or who are nonresident or unknown, their heirs, devisees, executors, administrators, and assigns; and the proceedings or sale of such real estate shall not be rendered invalid if the true owner or owners or any other person or persons having any right, title, or interest in said real estate shall not be included as a party to the suit, if it shall appear that the publication herein provided for shall have been duly made.
D.C. Code § 47-1313
Office of Assessor abolished: See Historical and Statutory Notes following § 47-413.
Documentary evidence, certified mail return receipts, see § 14-506. .