Verification of service or compensation that was not reported to TRS or that was reported but requires further documentation in order to be creditable must be made by the employer in a form prescribed by TRS. At the request of TRS, employers shall provide copies of any records or information regarding service or compensation, including but not limited to contracts, work agreements, salary schedules or addenda, board minutes, payroll records, employment records, or other materials that will assist TRS in making a determination. TRS may rely upon employer verifications of service or compensation or may conduct an investigation to determine whether verified service or compensation is eligible.