(1) If the Attorney General has probable cause to believe that a person has engaged in an act which is subject to action by the Attorney General, he may, and shall upon request of the commissioner, make an investigation to determine if the act has been committed and, to the extent necessary for this purpose, may administer oaths or affirmations, and, upon his own motion or upon request of any party, may subpoena witnesses, compel their attendance, adduce evidence, and require the production of any matter which is relevant to the investigation, including the existence, description, nature, custody, condition and location of any books, records, documents or other tangible things and the identity and location of persons having knowledge of relevant facts, or any other matter reasonably calculated to lead to the discovery of admissible evidence.
