I stand corrected. According to Illinois penal code found at
Illinois General Assembly - Illinois Compiled Statutes, the fact that they robbed him after the assault is what elevated it to 1st degree murder. I've never heard of it being like that. In every state I've lived in, the definition of 1st degree murder has been what I laid out in the previous comments. I guess it is a kudos for Illinois...they sure don't get many on this forum. Hope the prosecutors can pull it off, but they'll probably plea it down to a lesser charge.
Most if not all states have a Felony Murder Statue:
Ind. Code § 35-42-1-1 : Indiana Code - Section 35-42-1-1: Murder
A person who:
(1) knowingly or intentionally kills another human being;
(2) kills another human being while committing or attempting to commit arson, burglary, child molesting, consumer product tampering, criminal deviate conduct, kidnapping, rape,
robbery, human trafficking, promotion of human trafficking, sexual trafficking of a minor, or carjacking;
(3) kills another human being while committing or attempting to commit:
(A) dealing in or manufacturing cocaine or a narcotic drug (IC 35-48-4-1);
(B) dealing in or manufacturing methamphetamine (IC 35-48-4-1.1);
(C) dealing in a schedule I, II, or III controlled substance (IC 35-48-4-2);
(D) dealing in a schedule IV controlled substance (IC 35-48-4-3); or
(E) dealing in a schedule V controlled substance; or
(4) knowingly or intentionally kills a fetus that has attained viability (as defined in IC 16-18-2-365);
commits murder, a felony.