Whenever, in the absence of a fire-warden, a forest, woodlot, or wild land fire shall be extinguished or combatted by persons without first having been employed by said warden, such persons shall receive the compensation allowed by this act: Provided, That after a thorough investigation by the district fire-warden, wherein he shall have power and authority to examine persons under oath or affirmation, administered by himself, he shall have ascertained, as a result of his investigation, the facts hereinbefore required to be included in his report to the Commissioner of Forestry,¹ the truth of which he shall first have fully demonstrated to his own satisfaction: Provided further, That if his investigation shall disclose that any person, so claiming compensation, set the fire, or in any manner, carelessly, negligently, or maliciously, contributed to its burning, such person not only shall not be allowed any compensation, but shall be proceeded against criminally, if in the judgment of the Commissioner of Forestry the evidence shall warrant such prosecution.