Martin Luther King Jr's confidant, who was a well-known photographer of the US civil rights era, was a FBI informant, it has emerged.
Ernest Withers, who died in 2007 at the age of 85, took some of the most famous pictures of King, including him riding one of the first desegregated buses in Montgomery, Alabama, reports the Telegraph.
Known as the "original civil rights photographer," he also captured thousands of images chronicling lives of every day struggle in the Deep South, along with demonstrations, riots and criminal trials.
But, unknown to King and other civil rights leaders, Withers was also passing photographs of them, their biographical details, summaries of their political beliefs, and even their car licence plate numbers to the government.
He informed on pastors and political candidates, and alerted the FBI to planned demonstrations.
The day before Dr King's death Withers had been taking photographs of him, but he had also been telling the FBI about a meeting of suspected black militants.
Withers' FBI role has been revealed by a two-year investigation by Memphis newspaper The Commercial Appeal, who obtained some of his files under the Freedom of Information Act.
The FBI refused to release his entire file but did disclose 369 pages of documents in which Withers was mostly referred to by his informant code number ME 338-R.
Rosalind Withers, one of Withers' daughters, rejected the disclosure, and said: "My father's not here to defend himself. That is a very, very strong accusation."
Athan Theoharis, a historian at Marquette University, Wisconsin said: "It is an amazing betrayal. It really speaks to the degree that the FBI was able to engage individuals within the civil rights movement. This man was so well trusted."
