(a) When it appears to the Attorney General that a person has engaged in, is engaging in, or is about to engage in any act or practice declared to be unlawful by this article, or when he believes it to be in the public interests that an investigation should be made to ascertain whether a person in fact has engaged in, is engaging in, or is about to engage in any act or practice declared to be unlawful by this article, he may execute in writing and cause to be served upon that person or any other person who is believed to have information, documentary material or physical evidence relevant to the alleged or suspected violation, an investigative demand requiring such person to furnish, under oath, a report in writing setting forth the relevant facts and circumstances of which he has knowledge, or to appear and testify or to produce relevant documentary material or physical evidence for examination and copying, at such reasonable time and place as may be stated in the investigative demand, concerning the advertisement, sale or offering for sale of any goods or services or the conduct of any trade or commerce that is the subject matter of the investigation.

(b) At any time before the return date specified in an investigative demand, or within twenty days after the demand has been served, whichever period is shorter, a petition to extend the return date for a reasonable time or to modify or set aside the demand, stating good cause, may be filed in the court of common pleas where the person served with the demand resides or has his principal place of business or conducts or transacts business. This section shall not be applicable to any criminal proceedings, nor shall any information obtained under the authority of this section or § 39-5-80 be admissible in evidence in any criminal prosecution.