Read the FBI's 'suicide note' to Martin Luther King Jr.

The Rev. Dr. Martin Luther King Jr. (AP/File)

A 1964 letter sent by an anonymous FBI agent to the Rev. Martin Luther King Jr. threatened to expose the civil rights leader's extramarital affairs unless he took the "one way out" — an apparent reference to suicide.

“You are done," says the agent, posing as a civil rights supporter. "There is but one way out for you. You better take it before your filthy, abnormal, fraudulent self is bared to the nation.”

The one-page, typewritten letter — which will be published in the New York Times Magazine on Sunday — addresses King as an “evil, abnormal beast," giving him 34 days to kill himself or face being outed as a womanizer.

“King, look into your heart," the letter says. "You know you are a complete fraud and a great liability to all of us Negroes."

The note was recently discovered in the National Archives in College Park, Md., by Yale history professor Beverly Gage as she was researching a biography of former FBI Director J. Edgar Hoover.

An edited version of the so-called "suicide letter" had already been published. But the unredacted, largely-misspelled missive shines a disturbing light on the well-documented efforts of Hoover to discredit King.

The letter references an audio recording as evidence of King's adultery and directs him to listen to it.

“Lend your sexually psychotic ear to the enclosure,” the note reads. "You are a colossal fraud and an evil, vicious one at that.”

The final paragraph makes one final, veiled threat: “There is only one thing left for you to do. You know what it is.”

According to Gage, when King received the letter he told friends that he suspected Hoover was behind it.

A few days after Hoover denounced King at a Nov. 18, 1964, new conference as “the most notorious liar in the country,” FBI agent William Sullivan, one of Hoover's deputies, "apparently took it upon himself to write the anonymous letter and sent an agent to Miami, to mail the package to Atlanta," Gage wrote in the Times.

In December 1964, King became the youngest man ever to be awarded to the Nobel Peace Prize. He was assassinated four years later.

Read the full letter below:

(Courtesy National Archives, College Park, Maryland)
(Courtesy National Archives, College Park, Maryland)