Tex. Gov't Code § 815.505

Not later than the 12th day of the month following the month in which a person begins or ceases employment as a law enforcement officer or custodial officer, the governmental entity that employs or ceased employing the law enforcement officer or custodial officer, as applicable, shall certify to the retirement system, in the manner prescribed by the system, the name of the employee and such other information as the system determines is necessary for the crediting of service and financing of benefits under this subtitle.