(a) Unless both parties with the consent of the court waive the right to have the sentence hearing conducted before a jury as provided in Section 13A-5-44(c), it shall be conducted before a jury which shall return a verdict as provided by subsection (e) of this section. If both parties with the consent of the court waive the right to have the hearing conducted before a jury, the trial judge shall proceed to determine sentence without a verdict from a jury. Otherwise, the hearing shall be conducted before a jury as provided in the remaining subsections of this section.

(b) If the defendant was tried and convicted by a jury, the sentence hearing shall be conducted before that same jury unless it is impossible or impracticable to do so. If it is impossible or impracticable for the trial jury to sit at the sentence hearing, or if the case on appeal is remanded for a new sentence hearing before a jury, a new jury shall be impanelled to sit at the sentence hearing. The selection of that jury shall be according to the laws and rules governing the selection of a jury for the trial of a capital case.

(c) The separation of the jury during the pendency of the sentence hearing, and if the sentence hearing is before the same jury which convicted the defendant, the separation of the jury during the time between the guilty verdict and the beginning of the sentence hearing, shall be governed by the law and court rules applicable to the separation of the jury during the trial of a capital case.

(d) After hearing the evidence and the arguments of both parties at the sentence hearing, the jury shall be instructed on its function and on the relevant law by the trial judge. The jury shall then retire to deliberate concerning the verdict it is to return.

(e) After deliberation, the jury shall return a verdict as follows:

(1) If the jury determines that no aggravating circumstances as defined in Section 13A-5-49 exist, it shall return a verdict of life imprisonment without parole;

(2) If the jury determines that one or more aggravating circumstances as defined in Section 13A-5-49 exist but do not outweigh the mitigating circumstances, it shall return a verdict of life imprisonment without parole;

(3) If the jury determines that one or more aggravating circumstances as defined in Section 13A-5-49 exist and that they outweigh the mitigating circumstances, if any, it shall return a verdict of death.

(f) The decision of the jury to return a verdict recommending a sentence of life imprisonment without parole must be based on a vote of a majority of the jurors. The decision of the jury to recommend a sentence of death must be based on a vote of at least 10 jurors. The verdict of the jury must be in writing and must specify the vote.

(g) If the jury is unable to reach a verdict recommending a sentence, or for other manifest necessity, the trial court may declare a mistrial of the sentence hearing. Such a mistrial shall not affect the conviction. After such a mistrial or mistrials another sentence hearing shall be conducted before another jury, selected according to the laws and rules governing the selection of a jury for the trial of a capital case. Provided, however, that, subject to the provisions of Section 13A-5-44(c), after one or more mistrials both parties with the consent of the court may waive the right to have a verdict from a jury, in which event the issue of sentence shall be submitted to the trial court without a recommendation from a jury.