The legislative authority of a municipal corporation may invest any officer of the fire or police department with the power, and impose on him the duty, to be present at all fires, investigate the cause thereof, examine witnesses, compel the attendance of witnesses and the production of books and papers, and to do and perform all other acts necessary to the effective discharge of such duties.
Such officer may administer oaths, make arrests, and enter, for the purpose of examination, any building which, in his opinion, is in danger from fire. The officer shall report his proceedings to the legislative authority at such times as are required.