SECTION 1. Chapter 265 of the General Laws is hereby amended by striking out section 1 and inserting in place thereof the following section:-

Section 1. (a) Murder committed with deliberately premeditated malice aforethought, or with extreme atrocity or cruelty is murder in the first degree. Murder which does not appear to be in the first degree is murder in the second degree. Petit treason shall be prosecuted and punished as murder. The degree of murder shall be found by the jury.

(b) Whenever a death occurs in the commission or attempted commission of a crime punishable with death or imprisonment for life, unless there is a showing of deliberately premeditated malice aforethought, extreme atrocity or cruelty, whoever is found to have committed or attempted to commit such crime shall be punished by imprisonment in the state prison for a term of no less than 15 years nor more than 25 years to life.

SECTION 2. Notwithstanding any other provision of law, subsection (b) of section 1 shall apply to any person charged or convicted with murder in the first degree prior to, on or after the effective date of this act.