11. Any person refusing to be sworn when duly required, or omitting or refusing, without just cause, sufficiently to answer any question that may be lawfully put to him, or to render any testimony in virtue of this act, shall be deemed to be in contempt of court and shall be punished accordingly.
No answer given, however, by any person so heard as a witness, may be used against him in any prosecution under any act of the Legislature, if the commissioners have given him a certificate establishing that he has claimed the right to be excused from answering, and has given full and truthful answers to the satisfaction of the said commissioners.
R. S. 1964, c. 11, s. 11.