Make sure that you made all things on http://infamouspapertrail.com/ and return to the start point in Waterfront, where you've begun the previous secondary mission. When you connect with your profile, press Up to begin a new mission. At first, you have to get to the northern part of Rainier. Pass policemen set up around the marker and approach the manhole to get into Eugene's cellar.
You've visited this place in the eleventh main mission. This time, there no battles to be made. Start exploring the hideout. You find a murdered judge. Search the scene, making two photos of Paulson's limbs and then pick up his Wallet.
Now you can head for the exit. Pick up the new Origami Dove and after that return to the center of Rainier. Move away from the area guarded by the policemen and wait until proofs are send to your Paper Trail profile.