First degree murder is generally defined, these days, as any willful, premeditated, intentional murder with malice aforethought.
The key to first and second degree murder is the premeditation.
As my Criminal Law professor once explained it:
If you come home and find your spouse in bed with another person and pull your gun and shoot them both it is second degree murder. If you come home and find your spouse in bed with another person and run to your closet to get your gun and then you shoot them both it is first degree murder.
There will be variations in the definitions state to state but that is a sufficient way to look at it generally.
In the case at hand, had the store clerk pulled his gun in the heat of their argument and shot the victim it would be second degree murder. Allowing the victim to walk out and then chasing after him to shoot him makes it first degree murder.
I think it is that simple, barring definitional variations in different jurisdictions.
The key to first and second degree murder is the premeditation.
As my Criminal Law professor once explained it:
If you come home and find your spouse in bed with another person and pull your gun and shoot them both it is second degree murder. If you come home and find your spouse in bed with another person and run to your closet to get your gun and then you shoot them both it is first degree murder.
There will be variations in the definitions state to state but that is a sufficient way to look at it generally.
In the case at hand, had the store clerk pulled his gun in the heat of their argument and shot the victim it would be second degree murder. Allowing the victim to walk out and then chasing after him to shoot him makes it first degree murder.
I think it is that simple, barring definitional variations in different jurisdictions.