Section 3A. The commissioner shall administer and enforce the provisions of this chapter, chapter one hundred and fifty-six B insofar as made applicable under this chapter, except section eleven of said chapter one hundred and fifty-six B, chapter one hundred and seventy-six. If upon complaint, examination or other evidence exhibited to him he is of the opinion that any provision of said chapters has been violated, he shall forthwith report the facts to the attorney general or to the proper district attorney who shall cause the offender to be prosecuted therefor.