Elphaba’s face darkened again. Then she asked, hesitantly, as if afraid of the answer, “So, how do you get the evil life force?”“From innocent people, Elphaba,” Nick spoke so quietly he almost whispered. “I must draw the life force from innocent people. The more innocent they are, the more evil the murder 
Abramelin Keldor, The Goodwill Grimoire
detective, paranormal