D.C. Code § 8-504
No dealer shall be prosecuted under the provisions of this chapter when he can establish a guaranty signed by the manufacturer residing in the United States from whom he purchases mattresses to the effect that the statements contained on the labels attached to such mattresses are true. Such guaranty, to afford protection, shall contain the name and address of the manufacturer making the sale of such mattresses to the dealer, and in such case the manufacturer shall be amenable to the prosecutions, fines, and other penalties which would attach, in due course, to the dealer under the provisions of this chapter. In case the manufacturer resides outside the District of Columbia it shall be the duty of each United States Attorney to whom the Director of the Department of Human Services of the District of Columbia shall report the violation to cause appropriate proceedings to be commenced and prosecuted against the manufacturer without delay in the proper courts of the United States.
D.C. Code § 8-504