A new biography of black radical activist Malcolm X has repeated claims that he was bisexual.

According to ‘Malcolm X: A Life of Reinvention’, he had a relationship with a white businessman.

The book, which also claimed that the black rights leader’s real killer escaped justice, was published a few days after its author Manning Marable died.

Mr Marable was one of America’s most respected African-American scholars and his work has been welcomed by gay rights campaigners.

The claims about Malcolm X’s bisexuality were first made in a 1991 book, ‘Malcolm: The Life of a Man Who Changed Black America’ by Bruce Perry.

That biography claimed that the leader had worked as a male prostitute and had same-sex experiences from an early age.

Gay rights activist Peter Tatchell, who has been pushing for recognition of the leader’s alleged sexual orientation, said he and Mr Perry had been accused of racism and revisionism by Malcolm X’s supporters.

He said: “Manning Marable was a widely respected historian with great credibility in academic, black and left-wing circles.

“His corroboration of Malcolm X’s same-sex experiences will hopefully help undermine the decades of denialism by those who misguidedly regard homosexuality as shameful and un-African.”

Malcolm X was assassinated in Manhattan in 1965 at the age of 39. Three men were convicted of his murder but Mr Marable claimed that the real killer is 72-year-old Al-Mustafa Shabazz, who lives in New York.

The book also alleged that the New York Police Department had been forewarned of the assassination and had bungled the investigation.

These claims were dismissed by an NYPD spokesman as “gratuitously false “.