The examiner or examiners so appointed shall have power to issue subpoenas for witnesses, which shall be served by the sheriff of the proper county or by any special constable appointed by such examiner or examiners, to compel the attendance of witnesses by attachment, to punish for contempt by fine or imprisonment in the county jail and to administer oaths to witnesses, and the oaths administered by such examiners shall, in all respects, be deemed and held to be lawful oaths.