(a) The grand jury convened pursuant to this part shall consist of thirteen (13) members and up to five (5) alternates.
(b) The alternates shall be present at all times during grand jury proceedings, but shall not take part in the deliberations or vote of the grand jury unless the alternate has been made a regular member of the grand jury upon motion of the district attorney general made to the court and alleging that a regular member is no longer able to serve.
(c) Any grand jury ordered convened pursuant to this part shall be:

(1) Impaneled by the presiding judge in the same manner as the regular grand jury;
(2) Directed by the presiding judge to investigate the crimes specified in the petition; however, nothing in this subsection (c) shall be construed as preventing indictment for any offense found by the grand jury to have occurred in the course of its investigation; and
(3) Retain all powers, duties and responsibilities of the regular grand jury.