The said State Fire Marshal shall, when in his opinion further investigation is necessary, take or cause to be taken the testimony on oath of all persons supposed to be cognizant of any facts or to have means of knowledge in relation to the matter as to which an examination is herein required to be made, and shall cause the same to be reduced to writing; and if he shall be of the opinion that there is evidence sufficient to charge any person with the crime of arson, or with the attempt to commit the crime of arson, or of conspiracy to defraud, or criminal conduct in connection with such fire, he shall cause such person to be arrested and charged with such offense, or either of them shall furnish to the proper prosecuting attorney all such evidence, together with the names of witnesses and all information obtained by him including a copy of all pertinent and material testimony taken in the case, and shall report to the Insurance Commissioner as often as such commissioner shall require, his proceedings, and the progress made in all prosecutions under this act,¹ and the result of all cases which are finally disposed of.