The Department of Public Safety is hereby authorized to pay into the Police Officers’ Retirement System fund prior to July 1, 1967, on behalf of active highway patrol member employees, an amount equal to the sum such members would be required to contribute to the fund for creditable prior service pursuant to § 9-11-170. The amounts paid into the fund shall be used for the payment of retirement benefits under the Police Officers’ Retirement System or shall be refunded to the Department of Public Safety. None of the moneys paid into the fund pursuant to this section shall be disbursed in any other manner to patrol member employees upon termination of employment with the department nor shall any such funds be paid to a patrol member employee’s surviving beneficiary as a residual credit to any patrol member employee’s account which may have existed upon his death. Provided, however, that the interest accruing after July 1, 1967 on the amount paid into the fund may be credited to the patrol member employee’s account just as if he had made the contribution for creditable prior service for his account. Any time that the Police Officers’ Retirement System closes the account of an active patrol member employee because of death or termination of employment with the department the System shall refund to the department the amount that it has paid into the fund on behalf of patrol member employees for creditable prior service under the Supplemental Allowance Program of the System.