Ernest Withers is considered one of the great documentary photographers of the civil rights movement.
He was a confidant of Martin Luther King, Medgar Evers and James Meredith. His photos of pivotal events in the movement -- the Montgomery Bus boycott, the Memphis sanitation workers' strike, the murder of Emmett Till -- can rightly be called iconic. There is a museum in Withers' home town of Memphis dedicated to his work.
But Withers had a secret: he was an FBI informant, and those iconic photos were often used by the Bureau to identify civil rights activists.
Memphis-based investigative journalist Marc Perrusqia has written an expose of Withers' double life, A Spy In Canaan.