Service of summons.

The summons provided for by section 16-1501 shall be served seven days, exclusive of Sundays and legal holidays, before the day fixed for the trial of the action. If the defendant has left the District of Columbia, or cannot be found, the summons may be served by delivering a copy thereof to the tenant, or by leaving a copy with some person above the age of sixteen years residing on or in possession of the premises sought to be recovered, and if no one is in actual possession of the premises, or residing thereon, by posting a copy of the summons on the premises where it may be conveniently read. If the summons is posted on the premises, a copy of the summons shall be mailed first class U.S. mail, postage prepaid, to the premises sought to be recovered, in the name of the person known to be in possession of the premises, or if unknown, in the name of the person occupying the premises, within 3 calendar days of the date of posting.