9 square miles. 10,000 criminals. 130 cops. Compton: the most violent and crime-ridden city in America. What had been a semirural suburb of Los Angeles in the 1950s became a battleground for the Black Panthers, home of the Crips and Bloods and the first Hispanic gangs, and the cradle of gangsta rap. At the center of it, trying to maintain order, was the Compton Police Department. Never more than 130 strong, it faced an army of criminals that numbered...