Head for the marker in the central part of Waterfront and use it to connect with your Paper Trail profile. If you make everything ok on the website (hacking the Fishbein's phone) game let you begin the fifth mission. You have to find Linda Kriley. Press Up to begin this mission.
Your current target is northern part of Rainier. When you get there, ignore the policemen around the building and get on one of the higher shelves. Here is the new crime scene. You have to perform standard investigation activities. So begin with photographing corpses in proper position (in two different places) and the document. Then approach the mentioned notepad and press touchpad to pick it up.
You can return to the place where you began this mission (Waterfront) to send forward the proofs. Leave the game for a while and log into the Paper Trail profile.