The brute caricature portrays black men as innately savage, animalistic, destructive, and criminal -- deserving punishment, maybe death. This brute is a fiend, a sociopath, an anti-social menace. Black brutes are depicted as hideous, terrifying predators who target helpless victims, especially white women.
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The "terrible crime" most often mentioned in connection with the black brute was rape, specifically the rape of a white woman. At the beginning of the twentieth century, much of the virulent, anti-black propaganda that found its way into scientific journals, local newspapers, and best-selling novels focused on the stereotype of the black rapist. The claim that black brutes were, in epidemic numbers, raping white women became the public rationalization for the lynching of blacks.
http://www.ferris.edu/jimcrow/brute/