Any funds created by sections 169.410 to 169.540 while in the charge and custody of the board of trustees of such retirement system shall not be subject to execution, garnishment, attachment or any other process whatsoever and shall be unassignable except as in sections 169.410 to 169.540 specifically provided or in the case of a proper order of child support issued through the family support division.
§ 169.520, RSMo