For the purpose of this subchapter, the term:
(1) “Court of the District of Columbia” means the Superior Court of the District of Columbia or the District of Columbia Court of Appeals.
(2) “Criminal investigator” means an individual authorized by the Mayor or the Mayor’s designated agent to conduct or engage in a criminal investigation, or a prosecuting attorney conducting or engaged in a criminal investigation.
(3) “Criminal investigation” means an investigation of a violation of any criminal statute in effect in the District of Columbia.
(4) “Official proceeding” means any trial, hearing, investigation, or other proceeding in a court of the District of Columbia or conducted by the Council of the District of Columbia or an agency or department of the District of Columbia government, or a grand jury proceeding.