Section 69. (a) In all cases in which the death penalty may be authorized, the statutory aggravating circumstances are:

(1) the murder was committed on a victim who was killed while serving in the performance of his official duties as one or more of the following: police officer, special police officer, state or federal law enforcement officer, firefighter, officer or employee of the department of correction, officer or employee of a sheriff's department, officer or employee of a jail or officer or employee of a house of correction;

(2) the murder was committed by a defendant who was at the time incarcerated in a jail, house of correction, prison, state prison or a correctional or penal institution or a facility used for the housing or treatment or housing and treatment of prisoners;

(3) the murder was committed on a victim who was killed while engaged in the performance of his official duties as a judge, prosecuting attorney, juror, or witness;

(4) the murder was committed by a defendant who had previously been convicted of murder in the first degree, or of an offense in any other federal, state or territorial jurisdiction of the United States which is the same as or necessarily includes the elements of the offense of murder in the first degree;

(5) the murder was committed by the defendant pursuant to a contract, agreement or understanding by which he was to receive money or anything of value in return for committing the murder;

(6) the murder was committed by the defendant for the purpose of avoiding, interfering with, or preventing a lawful arrest of the defendant or another, or the murder was committed by the defendant for the purpose of effectuating an escape or attempting to effectuate an escape of the defendant or another from custody in a place of lawful confinement;

(7) the murder involved torture to the victim or the intentional infliction of extreme pain prior to death demonstrating a total disregard to the suffering of the victim;

(8) the murder was committed as part of a course of conduct involving the killing of or causing serious bodily injury to or the attempted killing of or the attempted causing of serious bodily injury to more than one person by the defendant;

(9) the murder was committed by means of a destructive device, bomb, or explosive planted, hidden, mailed, delivered, or concealed in any place, area, dwelling, building, or structure by the defendant or the murder was committed by means such that the defendant knew or reasonably should have known that his act or acts would create a grave risk of death or serious bodily injury to more than one person; or

(10) the murder was committed by the defendant and occurred during the commission or attempted commission or flight after committing or flight after attempting to commit aggravated rape, rape, rape of a child, indecent assault and battery on a child under fourteen, assault with intent to rape, assault on a child under sixteen years of age with intent to rape, kidnapping for ransom, kidnapping, armed robbery, unarmed robbery, breaking and entering with intent to commit a felony, armed assault in a dwelling, arson, confining or putting in fear or otherwise harming another for the purpose of stealing from depositories, or the murder occurred while the defendant was in possession of a sawed-off shotgun or a machine gun.

(b) In all cases in which the death penalty may be authorized, the mitigating circumstances shall be any factors proffered by the defendant or the commonwealth which are relevant in determining whether to impose a sentence less than death, including, but not limited to, any aspect of the defendant's character, propensities, or record and any of the circumstances of the murder, including but not limited to the following:

(1) the defendant has no significant history of prior criminal convictions;

(2) the victim was a participant in the defendant's conduct or had consented to it;

(3) the murder was committed while the defendant was under extreme duress or under the domination or control of another;

(4) the offense was committed while the capacity of the defendant to appreciate the criminality of his conduct or to conform his conduct to the requirements of the law was impaired as a result of a mental disease or defect, organic brain damage, emotional illness brought on by stress or prescribed medication, intoxication, or legal or illegal drug use by the defendant which was insufficient to establish a defense to the murder but which substantially affected his judgment;

(5) the defendant was over the age of seventy-five at the time of the murder, or any other relevant consideration regarding the age of the defendant at the time of the murder;

(6) the defendant was battered or otherwise physically, sexually, or mentally abused by the victim in connection with or immediately prior to the murder for which the defendant was convicted;

(7) the defendant was experiencing post-traumatic stress syndrome caused by military service during a declared or undeclared war.