GEOFF BENNETT: This week marked the anniversary of the assassination of Malcolm X.

Since that day 58 years ago, there have been many difficult and painful questions about who may have been involved in his murder and what led to it.

This week, Malcolm X's family took new action, announcing their intent to sue several federal and local government agencies for allegedly concealing evidence about what happened.

ILYASAH SHABAZZ, Daughter of Malcolm X: We want justice served for our father.

GEOFF BENNETT: Malcolm X's daughter Ilyasah Shabazz still searching for answers decades after his assassination.

At a press conference this week, Shabazz, surrounded by family and civil rights attorney Ben Crump, announced plans to file a $100 million wrongful death lawsuit against the NYPD, the CIA, FBI and other government agencies.

ILYASAH SHABAZZ: For years, our family has fought for the truth to come to light concerning his murder.

And we'd like our father to receive the justice that he deserves.

GEOFF BENNETT: They allege a conspiracy in connection with Malcolm X's murder and a subsequent cover-up of evidence.

ILYASAH SHABAZZ: The truth about the circumstances leading to the death of our father is important, not only to his family, but to many followers, many admirers, many who look to him for guidance, for love.

GEOFF BENNETT: On February 21, 1965, Malcolm X was killed in a hail of bullets just as he was about to give a speech in the Audubon Ballroom in Harlem, as his pregnant wife and children ducked for safety.

He was 39 years old.

Three men were arrested and convicted of the crime.

In November 2021, after decades of doubts surrounding the case, and following the release of the Netflix documentary "Who Killed Malcolm X?"

the Manhattan district attorney reopened the case.

Two men who were convicted of murdering Malcolm X in 1966 were exonerated after serving decades in prison.

And the district attorney admitted that the FBI and NYPD at the time withheld evidence.

BENJAMIN CRUMP, Attorney for Family of Malcolm X: The New York Police Department, the FBI, the district attorney of New York had factual evidence, exculpatory evidence that they fraudulently concealed from the men who were wrongfully convicted for the assassination of Malcolm X.

And they also fraudulently concealed that information, most importantly, from the family of Malcolm X. GEOFF BENNETT: The FBI, CIA and NYPD did not respond to the "NewsHour"'s requests for comments.

The lawsuit could help put to rest decades of controversy and conspiracy theories that have swirled in the more than 50 years since his assassination.

Leading Malcolm X historian Abdur-Rahman Muhammad sees the suit as the culmination of years of work investigating the assassination.

ABDUR-RAHMAN MUHAMMAD, Historian: I'm extremely gratified and really had no way of knowing going into this that it would culminate in such a spectacular victory.

I think it's unprecedented in U.S. history that that's ever happened.

And I'm extremely grateful and gratified to have lived long enough to see this day.

GEOFF BENNETT: As for Malcolm X's family, they say they want their father to receive the justice he deserves.