Honestly, I have lost faith in our Law Enforcement agencies, and would not be surprised to see the man walk.
But in analyzing this encounter (And you can be sure, many instructors in self-defense courses are likely going to use this case, since it appears to be classic to me) the murderer clearly escalated it. Being the armed entity, he is obligated by law not to escalate the situation, or he will pay the price.
I sure hope he does pay the price.
On a side note, it appears pepper spray isn’t effective at all for self defense.