Head towards the marker in the central part of the Market District and interact with it to connect to your inFamous Paper Trail profile. If you have taken all of the steps, on the game's web page, properly (obtaining the ID and entering it into Delsin's phone) you will be allowed to start the twelfth mission and it is going to be about tracking down Tyler Bennet, who is using a pseudonym "Purity_Now". Press UP on the D-Pad to start the mission.
The game will now start the process of tracking down the person that you are looking for and, if you want to use the phone's readings, you first need to reach the rooftop of one of the buildings. The tracking app will direct you towards the small dock shown in the above screenshot, in the Southern part of Georgetown.
Head down the Eastern pier (the bigger one) Southwards and reach the staying place of Tyler Bennet, after several moments. If you are playing as the villain (bad karma), you need to kill him (the Square). If you are playing as the hero (good karma), you only need to knock him down (the Triangle).
Regardless of what you did, pick up the Threat List from the pier. Try to leave the docks, thanks to which there will appear Celia around. Collect the Origami Dove that she left behind. You now need to exit the game and log on to your inFamous Paper Trail profile.