(1) Every person held to answer a criminal charge may object to the competency of anyone summoned to serve as a grand juror, before he is sworn, on the ground that he is the prosecutor or complainant upon any charge against the person or that he is a witness on the part of the prosecution and has been summoned or bound in a recognizance as such.
(2) If the objection is established, the person so challenged shall be set aside and another juror summoned.