Catch Mode
Right after you get out of the sewers (Tunnel), there is a big area and 2 ghosts, kill every thing first, then go to the middle of it where u see a arc that leads up onto a building, throw a grenade down and jump by it to get enough height to start climbing it. When you get to the top take a left and hug the wall around the structure and the skull will be there.It says Catch.