§ 10. Power to investigate before grant. Before granting any lands or any interest therein, including lands under water, the commissioner of general services may summarily inquire into the rights of the person applying for such grant, on such proof as, by regulation, the commissioner may prescribe. The commissioner may take testimony and proofs in any matter or application before him, and the fees of witnesses and the expense of procuring their attendance shall be paid from the state treasury out of any funds available therefor by appropriation, on the audit and warrant of the comptroller, on the certificate of the commissioner. The commissioner shall establish reasonable rules to guard against false or fraudulent applications and for such other purposes as he may deem proper. At any such inquiry or hearing, the commissioner may be represented by a deputy or other representative designated by him.