In 1964, Martin Luther King Jr. received an anonymous letter assailing him as an "evil" fraud and threatening to reveal all kinds of sordid details about his personal life. Unless: "There is only one thing left for you to do," it concludes. "You know what it is." As Yale professor Beverly Gage explains in the New York Times, King read the letter and concluded that it could only have come from the FBI and that it was J. Edgar Hoover's way of getting him to kill himself. Historians have long known about the so-called "suicide letter," but Gage has discovered an unredacted version in Hoover's files in the National Archives, and the Times has published it here. (Though the newspaper redacts the name of a woman the letter writer calls one of his "evil playmates.")
The letter also makes reference to an "enclosure" and says King should listen to it, suggesting that it could be an audio recording related to one of his affairs. Gage writes that Hoover isn't the author—instead one of his deputies, William Sullivan, "apparently took it upon himself" to write it. For the record, the letter never explicitly says King should commit suicide, and some historians think the intent was to get him to step aside as a civil rights leader, not kill himself. Also for the record, King shows up at the top of "most popular Americans" lists decades later, while Hoover is nowhere in sight.