Let me give you the run down of what I have thus far. I've made some changes to the initial plot line.
I have two options as it stands now. I'm leaning toward the latter. My first idea is to have the victim soul, the dead hooker, make a pact with a dark force of some kind while in Inferno. Maybe with one of the death angels. I'm hoping that one may have some kind of rivalry with Gamalael... but I don't know if the Angels interact much. The second is a once popular psychic (in a similar vein as John Edwards of 'Crossing Over' fame) who made some horrible discoveries while investigating satanic abuse cases in the 80's and disappeared from the public eye. The psychic, investigating a sexual themed, abuse cult discovers occult links to a porno/death ring that has ties to Gamalael and makes contact with the most recent victim. He frees her soul from Inferno and it finds a host in the player's body.
Meanwhile the Nepharite that was charged with tormenting her will now be set upon the earth to find her, but he won't do it by his own body. He'll possess people on earth (like the movie Fallen) and move from body to body trying to destroy the host body and bring the rogue soul back to hell.
So, more or less, there is going to be a central player in the story with everyone else playing support roles. Some characters will be contacted by the rogue soul while the PC sleeps at night, others will have their own motivations for hunting down the Snuff ring. But the ultimate goal is to find the center of the snuff ring, kill all those involved and the players will realize that there is a lot more to it than just porno/death movies... I just haven't figured out what that will be yet.