(a) Sections 203.4 through 203.8 shall be applicable to a witness who is sworn in a proceeding pursuant to a Commission order for investigation or examination, such proceeding being hereinafter referred to as a formal investigative proceeding.

(b) Formal investigative proceedings may be held before the Commission, before one or more of its members, or before any officer designated by it for the purpose of taking testimony of witnesses and received other evidence. The term officer conducting the investigation shall mean any of the foregoing.