Md. Code, Business Occupations and Professions § 13–702

(a) Unless authorized under this title to engage in business for the purpose of providing private detective services, a person may not represent to the public, by use of a title, including “licensed private detective agency”, “private detective agency”, “private detectives”, or “private investigators”, by description of services, methods, or procedures, or otherwise, that the person is authorized to engage in the business of providing private detective services in the State.

(b) Unless an individual is certified as a private detective under this title, the individual may not represent to the public, by use of a title, including “certified private detective”, “licensed private detective”, “private detective”, or “private investigator”, by use of a badge or identification card, by description of services, methods, or procedures, or otherwise, that the individual is authorized to provide private detective services in the State.