(a) Summons. State grand jurors are summoned and impaneled as provided by statute and Rule 12.

(b) Assistance. The Supreme Court Chief Justice must designate the assignment judge for a state grand jury, as provided in A.R.S. § 21-421. The presiding judge and jury commissioner in each county must assist the assignment judge in impaneling a state grand jury. At the assignment judge's direction, the jury commissioner of each county must submit to the assignment judge, by a date set by that judge, a specified number of prospective jurors selected at random. The total number of prospective jurors must be based on reasonably proportional representation for each county according to the most recently published federal statewide census, and should include no less than 3 prospective state grand jurors from each county.

(c) Preliminary Selection. With the assistance of the jury commissioner in the county in which the assignment judge is serving, the assignment judge must send a questionnaire to each prospective state grand juror. From those prospective state grand jurors who return questionnaires and who are qualified and not excused, the jury commissioner must select at random a number of them sufficient for the final selection of state grand jurors. Each person must be summoned to appear before the assignment judge for final selection. The jury commissioner must keep a permanent record of the reason for excusing a prospective state grand juror.

(d) Examination. Each prospective state grand juror must be examined under oath or affirmation to confirm that the prospective juror is qualified to be a state grand juror; that service as a state grand juror would not impose an undue hardship; and that the prospective juror will act impartially and without prejudice. Inquiry also may be made about other relevant subjects. A verbatim record of this examination must be made, transcribed, and filed with the superior court clerk of the county in which the assignment judge is serving.