Maryland Code, Real Property § 8-303

(a) An action of distress shall be brought by the landlord as plaintiff, the landlord's petition shall name the tenant as defendant and contain the following information:

(b) The petition shall be under oath or affirmation of the plaintiff, or the plaintiff's agent, that the facts recited are true and correct.

(c) If a defendant is not a resident of, or amenable to service in a county where the leased premises are located, service may be made by certified mail, return receipt requested, bearing a postmark from the United States Postal Service. If this service is returned by the Post Office Department or refused by the addressee or the addressee's agent, then process shall be sent by first-class mail and the defendant returned as summoned.