Maryland Code, General Provisions § 5-516

(1) a written statement from any person, accompanied by an affidavit, setting forth the facts on which the statement is based;

(2) motion of a majority of the membership of the Joint Ethics Committee; or

(3) referral of a matter to the Joint Ethics Committee by a presiding officer of the General Assembly as provided in § 2-706(a)(5) of the State Government Article.

(b)(1) The Joint Ethics Committee shall provide a copy of each complaint filed under subsection (a) of this section to the presiding officer of the house of the legislator who is the subject of the complaint.

(2) Based on the information contained in a complaint provided to a presiding officer under paragraph (1) of this subsection, if a presiding officer determines that it is inappropriate for a Joint Ethics Committee member from that house to consider a particular matter, the presiding officer shall appoint a substitute member to the Joint Ethics Committee for its consideration of the matter.