8. The commissioners shall have the same power of punishing contempt's and obstructions to their proceedings, as is given to Civil and Criminal Courts by the Code of Criminal Procedure, 1898, and shall have the same powers for the summons of witnesses, and for compelling the production of documents, and for the discharge of their duty under the commission, and shall be entitled to the same protection as the Zila and City Judges, except that all process to cause the attendance of witnesses or other compulsory process, shall be served through and executed by the Zila or City Judge in whose jurisdiction the witness or other person resides, on whom the process is to be served. When the commission has been issued to a Court, or other person or persons having power to issue such process in the exercise of their ordinary authority, they may also use all such power for the purposes of the commission.