Md. Code, Business Occupations and Professions § 13–301

(a) Except as otherwise provided in this title, a person shall be licensed by the Secretary as a private detective agency before the person may:

(1) conduct a business that provides private detective services in the State; and

(2) solicit to engage in a business that provides private detective services in the State.

(b) An individual or a firm may qualify for a license as a private detective agency.