I think it was foreshadowed when 'Riq and Ghost are talking about why Ghost killed Breezy... Ghost told him he gave him a second chance to change his mind but he didn't. Later, 'Riq asks Ghost again: "so you really want me to turn myself in?" I think that was his way of giving Ghost a second chance. He sealed his fate when he told 'Riq "yes".
Good theory. I figured that when he was telling him that shyt, it would come back somehow. I gotta say though, Tariq being the killer would be the wackest outcome. First of all, they have telegraphed that shyt since Tariq turned . They already said he's gonna be a part of the sequel. And the worst part is, this nikka's motive is so weak. He hates his dad for lying and trying to give him a better life. His dad has saved his ass numerous times, thusly demonstrating that he cares. He responds to this by getting more and more disrespectful at every turn. Now that this same man that you have shat on at every turn won't go to jail for your little bad ass you ready to kill him? So you can become the new Ghost...or rather Book II ?