(1) Examiners may conduct investigations described in the following subparagraphs, upon request of the applicant for review or ex officio, insofar as they determine that such investigation is necessary for proper consideration of the facts and issues involved in the request for review:
1. To conduct an in-person hearing with the applicant for review or any other interested person at a time and place designated by an examiner;
2. To examine documentary and other evidence that an examiner may require the applicant for review or any other interested person to submit;
3. To seek an independent expert opinion;
4. To investigate the place of business or any other place relevant to the case, making inquiries of the business owner, employees, and other interested persons and inspecting documents and other articles on the premises.
(2) When conducting inquiries and inspections described in paragraph (1)4, examiners shall carry a certificate indicating their authority and present it to interested persons.