(a) This section applies if:
(1) a county in which a district is located creates a county fire marshal under Subchapter B, Chapter 352, Local Government Code; or
(2) a municipality located in the district creates a municipal fire marshal.
(b) Not later than the 30th day after the creation of the county or municipal fire marshal, the jurisdiction of the district fire marshal in that county or municipality ceases. The new county or municipal fire marshal shall assume control over any pending investigations, court proceedings, or other matters being handled by the district fire marshal in the county or municipality.