Texas Health and Safety Code - HEALTH & SAFETY § 775.113. Additional Investigation Powers

(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.

(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.