What I think will happen but will not happen:
She tracks Iijima down, he'll try to attack her, but Gyaruo is also there so Iijima gets killed by Gyaruo in self-defense to save Maria-sensei. She offers to hand herself to the police and take the blame but Gyaruo doesn't want that. Instead, they either bury his body or make it look like a robbery murder or some sort.
Maria will manipulate him, then gets invited to the gang. She'll kill the fatso in a clever way while making herself present to the others so they don't suspect her, like a trap. She'll betray Gyaruo and kill him, or in a shocking twist, she leaves him alive for some reason.
Her grand plan will be to manipulate the ringleader's mum, and they both kill the father and son. Hahahaha