See, here is my thinking on why this is fake. There is going to be a great deal of effort to point fingers in the aftermath of all of this, and the blame game is going to be so totally excellent. It will keep the news busy for another year to come, I guarantee you. And there is much that is going to be made of the racial divide, and everyone knows all of that.
So someone posting what essentially amounts to an instant paper trail of data that could incriminate oneself when people who have all sorts of axes to grind in public and elsewhere strikes me as monumentally stupid. All it would take is for one talented unknown lawyer with an agenda who knows how to use Google to see this thread eventually, and then the fun begins. There is no statute of limitations on murder. Everyone knows this. No matter under what circumstances someone killed someone else, the very worst thing you can do is go talking about it in public. So no one would ever do that.
Which is why this is fake.