Nobody has been able to chase enough down to know what happened. Just know that the guy is dead, shot in the head and burned in a trunk, after he is suspected of giving pro-wilson testimony that contradicted his friend, Dorian Johnson. Dorian is now in protective custody apparently.
There is a *lot* more going on here than people appreciate. There's a reason why Dorian was seen with a known agitator on camera right after the shooting. Why he lied about where he was, where he was going, and what happened. Why Piaget and the other girl lied. Why so many came out of the woodwork and lied. It's not because they wanted "justice", it's because there's a lot of power and money in getting things frothed up.
This little race war they have going on is *not* incidental.