You're a planner. You'd carefully plot each murder, and carry it out methodically. You'll kill them in one location and move them to another later, and you'll study up your forensic science. The good news is, you're much harder to catch.
You'll have a specific reason to kill. You'll target a specific group, like prostitutes or members of a minority, and you'll believe their deaths are justified on the grounds that you're "cleansing" the earth of that particular kind of people. You'll think you're helping society.