Extortion, in common law, an act of a public official who uses his or her position to obtain money or property illegally. Many states define the crime more broadly to include blackmail and similar acts committed by anyone.
What makes a person not only murder, but murder multiple people over days, weeks and even years? There's a special name for these types of murderers: serial killers.
Few incidents shaped the U.S. civil rights movement more than the brutal death of Emmett Till. What other murders have sent shock waves through the public psyche?