From the Anti-Drug Abuse Act of 1988
Notwithstanding rule 32(c) of the Federal Rules of Criminal Procedure, when a defendant is found guilty of or pleads guilty to an offense under subsection (e) of this section, no pre-sentence report shall be prepared.  In the sentencing hearing, information may be presented as to matters relating to any of the aggravating or mitigating factors set forth in subsections (m) and (n) of this section, or any other mitigating factor or any other aggravating factor for which notice has been provided under subsection (h)(1)(B) of this section.  Where information is presented relating to any of the aggravating factors set forth in subsection (n) of this section, information may be presented relating to any other aggravating factor for which notice has been provided under subsection (h)(1)(B) of this section.  Information presented may include the trial transcript and exhibits if the hearing is held before a jury or judge not present during the trial, or at the trial judge's discretion.  Any other information relevant to such mitigating or aggravating factors may be presented by either the Government or the defendant, regardless of its admissibility under the rules governing admission of evidence at criminal trials, except that information may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury.  The Government and the defendant shall be permitted to rebut any information received at the hearing and shall be given fair opportunity to present argument as to the adequacy of the information to establish the existence of any of the aggravating or mitigating factors and as to appropriateness in that case of imposing a sentence of death.  The Government shall open the argument.  The defendant shall be permitted to reply.  The Government shall then be permitted to reply in rebuttal.  The burden of establishing the existence of any aggravating factor is on the Government, and is not satisfied unless established beyond a reasonable doubt.  The burden of establishing the existence of any mitigating factor is on the defendant, and is not satisfied unless established by a preponderance of the evidence.
 

Mitigating factors  
In determining whether a sentence of death is to be imposed on a defendant, the finder of fact shall consider mitigating factors,including the following:
(1) The defendant's capacity to appreciate the wrongfulness of the defendant's conduct or to conform conduct to the requirements of law was significantly impaired, regardless of whether the capacity was so impaired as to constitute a defense to the charge.
(2) The defendant was under unusual and substantial duress, regardless of whether the duress was of such a degree as to constitute a defense to the charge.
(3) The defendant is punishable as a principal (as defined in section 2 of title 18) in the offense, which was committed by another, but the defendant's participation was relatively minor, regardless of whether the participation was so minor as to constitute a defense to the charge.
(4) The defendant could not reasonably have foreseen that the defendant's conduct in the course of the commission of murder, or other offense resulting in death for which the defendant was convicted, would cause, or would create a grave risk of causing, death to any person. 
(5) The defendant was youthful, although not under the age of 18.  
(6) The defendant did not have a significant prior criminal record. 
(7) The defendant committed the offense under severe mental or emotional disturbance.
(8) Another defendant or defendants, equally culpable in the crime, will not be punished by death.
(9) The victim consented to the criminal conduct that resulted in the victim's death.
(10) That other factors in the defendant's background or character mitigate against imposition of the death sentence.  

(n) Aggravating factors for homicide  
If the defendant is found guilty of or pleads guilty to an offense under subsection (e) of this section, the following aggravating factors are the only aggravating factors that shall be considered, unless notice of additional aggravating factors is provided under subsection (h)(1)(B) of this section:  
(1) The defendant –  
    (A) intentionally killed the victim;  
    (B) intentionally inflicted serious bodily injury which resulted in the death of the victim;  
    (C) intentionally engaged in conduct intending that the victim be killed or that lethal force be employed against the victim, which resulted in the      death of the victim;
    (D) intentionally engaged in conduct which –
        (i) the defendant knew would create a grave risk of death to a person, other than one of the participants in the offense; and  
        (ii) resulted in the death of the victim.  
(2) The defendant has been convicted of another Federal offense, or a State offense resulting in the death of a person, for which a sentence of life imprisonment or a sentence of death was authorized by statute.
(3) The defendant has previously been convicted of two or more State or Federal offenses punishable by a term of imprisonment of more than one year, committed on different occasions, involving the infliction of, or attempted infliction of, serious bodily injury upon another person.
(4) The defendant has previously been convicted of two or more State or Federal offenses punishable by a term of imprisonment of more than one year, committed on different occasions, involving the distribution of a controlled substance.
(5) In the commission of the offense or in escaping apprehension for a violation of subsection (e) of this section, the defendant knowingly created a grave risk of death to one or more persons in addition to the victims of the offense.
(6) The defendant procured the commission of the offense by payment, or promise of payment, of anything of pecuniary value.
(7) The defendant committed the offense as consideration for the receipt, or in the expectation of the receipt, of anything of pecuniary value.
(8) The defendant committed the offense after substantial planning and premeditation.  
(9) The victim was particularly vulnerable due to old age, youth, or infirmity.  
(10) The defendant had previously been convicted of violating this subchapter or subchapter II of this chapter for which a sentence of five or more years may be imposed or had previously been convicted of engaging in a continuing criminal enterprise.  
(11) The violation of this subchapter in relation to which the conduct described in subsection (e) of this section occurred was a violation of section 859 of this title.
(12) The defendant committed the offense in an especially heinous, cruel, or depraved manner in that it involved torture or serious physical abuse to the victim.  


Jury Instruction Concerning Aggravating and Mitigating Factors
The jury, or if there is no jury, the court, shall consider all the information received during the hearing.  It shall return special findings identifying any aggravating factors set forth in subsection (n) of this section, found to exist.  If one of the aggravating factors set forth in subsection (n)(1) of this section and another of the aggravating factors set forth in paragraphs (2) through (12) of subsection (n) of this section is found to exist, a special finding identifying any other aggravating factor for which notice has been provided under subsection (h)(1)(B) of this section, may be returned.  A finding with respect to a mitigating factor may be made by one or more of the members of the jury, and any member of the jury who finds the existence of a mitigating factor may consider such a factor established for purposes of this subsection, regardless of the number of jurors who concur that the factor has been established.  A finding with respect to any aggravating factor must be unanimous.  If an aggravating factor set forth in subsection (n)(1) of this section is not found to exist or an aggravating factor set forth in subsection (n)(1) of this section is found to exist but no other aggravating factor set forth in subsection (n) of this section is found to exist, the court shall impose a sentence, other than death, authorized by law.  If an aggravating factor set forth in subsection (n)(1) of this section and one or more of the other aggravating factors set forth in subsection (n) of this section are found to exist, the jury, or if there is no jury, the court, shall then consider whether the aggravating factors found to exist sufficiently outweigh any mitigating factor or factors found to exist, or in the absence of mitigating factors, whether the aggravating factors are themselves sufficient to justify a sentence of death.  Based upon this consideration, the jury by unanimous vote, or if there is no jury, the court, shall recommend that a sentence of death shall be imposed rather than a sentence of life imprisonment without possibility of release or some other lesser sentence.  The jury or the court, regardless of its findings with respect to aggravating and mitigating factors, is never required to impose a death sentence and the jury shall be so instructed.