(a)    Cases In Which Court Has Discretion. In all cases in which the court has discretion as to what sentence may be imposed, the court may refer the case to the Department of Corrections for investigation and recommendation. No sentence or sentences other than probation or the statutorily required mandatory minimum may be imposed on any defendant found guilty of a first felony offense or found guilty of a felony while under the age of 18 years, until after such investigation has first been made and the recommendations of the Department of Corrections received and considered by the sentencing judge. The requirements of this subdivision are not applicable to a subsequent violation of probation proceeding.

(b)    Capital Defendant Who Refuses To Present Mitigation Evidence. Should a defendant in a capital case choose not to challenge the death penalty and refuse to present mitigation evidence, the court shall refer the case to the Department of Corrections for the preparation of a presentence report. The report shall be comprehensive and should include information such as previous mental health problems (including hospitalizations), school records, and relevant family background.