What the dead was, unfortunately, is all too common: a young black man with no impulse control.
Luckily this time the victim was able to defend himself. Actually, a very good shot: one round under the armpit as the attacker (armed) advanced is pretty good shooting.
They are the smart ones, and extremely dangerous.
The very successful ones learn from their police experiences as minors. Those records are sealed once they reach adulthood.
They learn how not to get caught.