§ 3-a. Restrictions upon holding public office or employment of persons removed from office for certain reasons. Any public officer who, upon being called before a grand jury to testify concerning the conduct of his office or the performance of his official duties, refuses to sign a waiver of immunity against subsequent criminal prosecution, or to answer any relevant question concerning such matters before such grand jury and who, by virtue thereof, has been removed from such public office by the appropriate authority or who has forfeited such office at the suit of the attorney general shall not be capable of holding a civil office or public employment for a period of five years from the date of the removal from or forfeit of such public office.