On DNA Row, at the building named Dermo Design, the first time you walk in the lower story (not the floor up the stairs), Moraji will be chained to a post and a bomb will be sitting on the table. Take your gun out and shoot the metal block restraining Moraji. You should hurry -- the bomb's timer is short. Then, run out of the building and stop away from the entrance. If you are near the entrance the explosion will kill you. Moraji will run out and the explosion will get him. However, he gives you a description of the attackers.