(a) If the fire marshal determines that further investigation of a fire or of an attempt to set a fire is necessary, the fire marshal may:
(1) subpoena witnesses to testify regarding the fire or attempt;
(2) administer oaths to the witnesses;
(3) take and preserve written statements, including statements under oath such as an affidavit or deposition; and
(4) require the production of a document or item related to the investigation.
(b) As part of an investigation, the fire marshal may:
(1) conduct an investigation or examination in private;
(2) exclude a person who is not under examination; and
(3) separate witnesses from each other until each witness is examined.