I don't want to sound heartless, but sounds like these kids are learning an important lesson on the dangers of gang-banging. How'd that old saying go? "Better check yourself, before you wreck yourself?"
Obviously it's a tragedy and I sympathize with the family, but when the father says, "He was done gang-banging," I think we should acknowledge that the finality of that statement is only true because of the kid's death. When the memorial pictures show you flashing gang signs...you're not really done with gang-banging.
The sad thing? I bet the family knows who did this and why. I bet they will never cooperate with the police. I bet the murder is never solved. That's just how things go in gangland. There are no innocent victims. You never snitch. And after a while, the police stop caring about dead gangbangers.