(a) (1) A law enforcement officer may make an inquiry and conduct a limited search of a person under paragraph (2) of this subsection if the officer, in light of the officer's observations, information, and experience, reasonably believes that:
(i) the person may be wearing, carrying, or transporting a handgun in violation of § 4-203 of this subtitle;
(ii) because the person possesses a handgun, the person is or presently may be dangerous to the officer or to others;
(iii) under the circumstances, it is impracticable to obtain a search warrant; and
(iv) to protect the officer or others, swift measures are necessary to discover whether the person is wearing, carrying, or transporting a handgun.
(2) If the circumstances specified under paragraph (1) of this subsection exist, a law enforcement officer:
(i) may approach the person and announce the officer's status as a law enforcement officer;
(ii) may request the name and address of the person;
(iii) if the person is in a vehicle, may request the person's license to operate the vehicle and the registration of the vehicle;
(iv) may ask any question and request any explanation that may be reasonably calculated to determine whether the person is unlawfully wearing, carrying, or transporting a handgun in violation of § 4-203 of this subtitle; and
(v) if the person does not offer an explanation that dispels the officer's reasonable beliefs described in paragraph (1) of this subsection, may conduct a search of the person limited to a patting or frisking of the person's clothing in search of a handgun.
(3) A law enforcement officer acting under this subsection shall take into account all circumstances of the occasion, including the age, appearance, physical condition, manner, and gender of the person approached.
(b) (1) If the officer discovers that the person is wearing, carrying, or transporting a handgun, the officer may demand evidence from the person of the person's authority to wear, carry, or transport the handgun in accordance with § 4-203(b) of this article.
(2) If the person does not produce the evidence specified in paragraph (1) of this subsection, the officer may seize the handgun and arrest the person.
(c) (1) A law enforcement officer who conducts a search or seizure in accordance with this section shall file a written report with the law enforcement officer's employer unit within 24 hours after the search or seizure.
(2) The report shall be on a form that the Secretary of Public Safety and Correctional Services prescribes, shall include the name of the person searched, and shall describe the circumstances surrounding and the reasons for the search or seizure.
(3) A copy of the report shall be sent to the Secretary of the State Police.
(d) On request of a law enforcement officer, the Attorney General shall defend the officer in a civil action, including any appeal, in which the officer is sued for conducting a search or seizure under this section that is alleged to be unreasonable and unlawful.
(e) (1) This section may not be construed to limit the right of a law enforcement officer to conduct any other type of search or seizure or make an arrest that is otherwise authorized by law.
(2) The provisions of this section are in addition to and not limited by the provisions of Title 2 of the Criminal Procedure Article.
Source - http://mlis.state.md.us/cgi-win/web_....exe?gcr&4-206