Section 21-3 - Establishment of investigating committees by legislature(a) An investigating committee may exercise its powers during sessions of the legislature, and also in the interim between sessions when so provided by law or by the concurrent or single house resolution or statute by which the committee was established or from which it derives its investigatory powers.(b) The concurrent or single house resolution or statute establishing an investigating committee shall state the committee's purposes, powers, duties and duration, the subject matter and scope of its investigatory authority, and the number of its members.