At the presentence hearing, following a finding that one or more of the circumstances enumerated in § 11-23-2 or 11-23-2.1 as the basis for imposition of a sentence of life imprisonment without parole was involved in the first degree murder of which the defendant has been convicted, the court shall consider evidence regarding the nature and circumstances of the offense and the personal history, character, record, and propensities of the defendant which are relevant to the sentencing determination. After hearing evidence and argument regarding the aggravating and mitigating circumstances relating to the offense and the defendant, the court shall, in its discretion, sentence the defendant to life imprisonment without parole or to life imprisonment. The court shall state on the record its reasons for imposing its sentence.