In determining the issues enumerated in subdivisions (1) and (2) of this subsection, the trier shall consider all evidence which it finds to be in aggravation or mitigation of punishment, including evidence received during the first stage of the trial and evidence supporting any of the statutory aggravating or mitigating circumstances set out in subsections 2 and 3 of this section. If the trier is a jury, it shall not be instructed upon any specific evidence which may be in aggravation or mitigation of punishment, but shall be instructed that each juror shall consider any evidence which he or she considers to be aggravating or mitigating.
§ 565.032, RSMo