Eventually some particularly egregious case, such as the beating of Rodney King in Los Angeles, causes a public outcry.

ECONOMIST: The police

Lemon reported for CNN's documentary Race and Rage: The Beating of Rodney King, which aired 20 years to the day of the beating.

CNN: About

As the executive director of an organization rocketed into existence 20 years ago because of a piece of media (the filming by a bystander of the beating of Rodney King by the Los Angeles police department), I firmly believe in the accelerating powers of visual media as applied to social progress.

FORBES: Up for Debate: How Personal Video Can Change the World