Drop your brief case as you won't need it and turn around. Go left and you should start to see a restaurant. From where you are, go straight into the back alley. Climb the ladder and drop your weapons up here. Now climb down and check your map. Go for the target that is at the top of the map. He is in a alley relieving himself. When he is at the sewer, strangle or shoot him with a silenced weapon. Take his clothes, the amulet, and drag his body over the sewers, and then drop it. He should fall down.
Now go the restaurant again. Go to the front where a guard will search you for weapons. When he is done, go inside and ask the bartender for the bathroom key. He will put them at the counter. Now go upstairs and meet with the blue lotus and the chief of police. After that, turn around and look right to see a door. Open it to the bathroom. Now look for a open window to climb through. A option should appear. Pick up your weapon.
Now climb back in, exit the bathroom, and kill the blue lotus leader and the chief. Aim for the head. When that is finished, put the amulet on the table where the blue lotus and chief were sitting. After that, go outside and check your map for finding a close exit. When you do that, you are done.