SEC. 4. No person shall be excused from attending and
testifying or from producing books, records, correspondence, documents, or other
evidence in obedience to a subpoena issued by the Commission on the ground that
his testimony or the evidence required of him may tend to incriminate him or
subject him to penalty or forfeiture; but his testimony or any evidence produced
by him shall not be used against him in connection with any transaction, matter
or thing concerning which he is compelled, after having claimed his privilege
against self-incrimination, to testify or produce evidence, except that such
individual so testifying shall not be exempt from prosecution and punishment for
perjury committed in so testifying, nor shall he be exempt from demotion or
removal from office.