The daughter of civil rights leader Malcom X plans to sue the CIA, FBI, the NYPD and other organisations over their alleged role in her father's death.
Ilyasah Shabazz has accused the federal and government agencies of fraudulently concealing evidence that they "conspired to and executed their plan to assassinate" the activist.
Her family announced a $100 million wrongful death lawsuit on the anniversary of Malcom's 1965 assassination.
Ms Shabazz was joined by her sister Qubilah and attorney Ben Crump at the site of the former Audubon Ballroom in upper Manhattan, where Malcolm was shot dead, aged 39.
For decades, questions have circulated over who was responsible for the Black Power activist's death.
Three men were convicted over the killing, but two were exonerated in 2021 following a renewed investigation into the cases against them.
It showed the evidence used to gain convictions was shaky and that authorities had held back some information.
Ilyasah Shabazz, co-administrator of her father's estate, has filed notices of legal action, claiming the agencies “conspired with each other and with other individuals and acted, and failed to act, in such a way as to bring about the wrongful death of Malcolm X".
She added: “For years our family has fought for the truth to come to light," she said at the news conference. “We want justice served for our father.”
Pointing to the 2021 exonerations, Mr Crump said government and law enforcement agencies “had factual evidence, exculpatory evidence that they fraudulently concealed from the men who were wrongfully convicted for the assassination of Malcolm X”.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know...
Asked if he believes government agencies conspired to assassinate Malcolm, Mr Crump said: “That is what we are alleging, yes. They infiltrated many civil rights organisations.”
Malcolm gained national prominence as the voice of the Nation of Islam, exhorting black people to claim their civil rights “by any means necessary.”
In 1964, near the end of Malcolm's life, he split with the Black Muslim organisation and, after a trip to Mecca, started speaking about the potential for racial unity, rather than separation.
It earned him the ire of some in the Nation of Islam, who saw him as a traitor, and drew death threats.