The feds have charged 6 people in connection with that killing, as a RICO predicate, but they probably will keep expanding their case, as some of these guys start talking.
If they can charge someone like Durk, they will. They would need witness statements, and probably texts, and then they can add things like music videos and rap lyrics to tie it all together, to tie him in his a co conspirator, or lead defendant, gang shot caller/leader.
but they won't come at someone like Durk, who has the finances and resources to dig in and fight the case, without something solid.