According to Bow Wow, the killer is Kanan Stark played by 50 Cent, who is also the executive producer of the show.
“I think my bro fif not dead! I know this sounds crazy… but ghost been seeing ghosts and talking to them and i think his mind so gone since his daughter died he dont know whats real or fake. I think the convo he had w fif was real. Fif was the only person left in the building and ghost new girlfriend. Who else would be able to kill him that fast. None of the suspects walking into the club ACTUALLY MADE IT INSIDE. They will show how fif aint die and maybe tariq had something to do with it by helping fif get in the place. Member there was a car following and watching ghost. Then the shoot out which they never showed who was tryna kill Ghost and Tommy.”