Upon return of the order, the judge before whom the matter shall come on for hearing shall examine such person under oath, and if the judge shall determine, after giving such person an opportunity to be heard, that he refused without legal excuse to comply with such subpoena or such order of the commissioners holding such investigation, the judge may order such person to comply therewith forthwith and any failure to obey the order of the judge may be punished as a contempt of the Superior Court.
N.J.S. § 5:8-17