Martin Luther King Jr. allegedly had sexual relations with at least 40 women, from prostitutes to people within his inner circle, according to explosive new research published Thursday by David J. Garrow, one of the civil rights leader’s foremost biographers.

The most shocking allegation, culled from decades-old FBI files, details a 1964 incident in which King reportedly “looked on, laughed and offered advice” to a fellow preacher who was raping a woman in a hotel room.

Garrow recounts other allegations from formerly sealed FBI documents – including that King fathered a love child and participated in an orgy with a female gospel legend — in an eight-page essay he wrote for Standpoint, a British cultural and political magazine.

The incidents emerged as part of a National Archives data dump related to the assassination of John F. Kennedy. In 2018, President Donald Trump ordered the release of more than 19,000 Kennedy-related documents. The documents include some surveillance summaries of FBI wiretaps of King between 1963 and 1966 in his home, office and hotel rooms, as well as information from informants who had infiltrated King’s circle.

The FBI allegations chronicled by Garrow could trigger a new examination of the civil rights hero’s personal life. Garrow is a prominent civil rights academic who won a Pulitzer Prize in 1987 for his King biography, “Bearing the Cross: Martin Luther King, Jr., and the Southern Christian Leadership Conference.”

“I have been the King guy for 40 years and I wrote a book on exactly this 38 years ago,” said Garrow, referring to his 1981 book, “The FBI and Martin Luther King Jr.” “I felt a complete obligation to confront this stuff. I did not feel I had a choice. I have always felt spiritually informed by King and yes, this changed it. I have not heard his voice much the past year.”