The family of Malcolm X, a militant civil-rights leader who was assassinated almost 60 years ago, filed a $100-million federal lawsuit on Friday that accuses the FBI, CIA and New York Police Department of allowing his murder to be carried out.

The lawsuit, brought by Malcolm X’s daughter Ilyasah Shabazz and other family members, alleges the law-enforcement agencies concealed evidence that they had known of the plot to kill him but did nothing to stop it.

“We believe that they all conspired to assassinate Malcolm X, one of the greatest thought leaders of the 20th century,” Ben Crump, a civil rights attorney who is representing the family, said at a press conference.

The wrongful-death lawsuit was announced at a memorial centre on the site in New York City where Malcolm X was killed.

It seeks to answer questions surrounding the assassination, and paint an accurate history of the events, Crump said.

It is also intended to bring reparations to the family.

A spokesperson for the New York Police Department was not immediately available for comment, but the department previously told Reuters it would not comment on the litigation when it was announced last year.

The FBI and the CIA did not immediately respond to requests for comment. Malcolm X became prominent as the national spokesperson of the Nation of Islam, an African American Muslim group that espoused Black separatism.

After more than a decade with the group, he publicly broke with it in 1964. He moderated some of his earlier views on racial separation, angering some Nation of Islam members and drawing death threats.

Talmadge Hayer, then a member of the Nation of Islam, confessed in court to being one of the three assassins.

But speculation that the government may have been aware of the assassination plan and allowed it to happen has persisted for decades.

Shabazz was just two years old on Feb 21, 1965, when her father was killed while preparing to speak at New York’s Audubon Ballroom.

She was present with her mother and siblings when the assassination took place.