My take is fake news and the fake security guard are f****d. The videos leaking out are really bad, I suspect undisclosed text messages and emails are even worse. Time will tell...
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.