When Malcolm X, the assassinated civil rights leader, was murdered on February 21, 1965, the crowd around him rushed to attempt to save his life, but to no avail. In the front row sat his pregnant wife and four daughters in the Audubon Ballroom, where he was the guest speaker. They saw Malcolm X shot and killed from only a few feet away, and the bullets were so close they had to duck to avoid getting shot.

Three men, members of the Nation of Islam, were charged with the assassination: Mujahid Abdul Halim, Muhammad A. Aziz and Khalil Islam, were quickly charged and convicted of first-degree murder.

For almost sixty years, family members and history experts questioned the validity of the convicted men’s guilt. Then, in 2021, after an investigation that discovered glaring errors in the murder case, two of the convicted men were exonerated.

The results of the probe led to imprisoned Aziz and Islam being exonerated and let out of prison. Halim, the third convicted man, who said he was one of the shooters, remains in prison.

At the time of the exoneration of Aziz and Islam, the founder of the Equal Justice Initiative summed up the situation clearly, saying “It’s long overdue. This is one of the most prominent figures of the 20th century who commanded enormous attention and respect. And yet, our system failed.”

This week, two years later, and on the anniversary of Malcolm X’s assassination, his family visited the Audubon Ballroom with their attorney and announced plans to sue the New York Police Department, the FBI, the CIA and the NY legal department.

They are seeking $100 million and accusing the federal and city authorities of playing a role in the death of their father and mishandling evidence.

The family alleges that the investigation that led to exonerating Aziz and Islam also showed that the authorities hid evidence and also that the evidence used to convict the alleged killers was weak.

Malcolm X’s daughter Ilyasah Shabazz, co-administrator of her father’s estate, filed notices of claim this week, as required before filing such lawsuits.

As she stood on the site where she saw her father murdered, Ms. Shabazz said the NYPD, CIA, and FBI, “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. For years our family has fought for the truth to come to light. We want justice served for our father.”

Ms. Shabazz was joined at the news conference on Tuesday by her sister, Qubilah Shabazz.

Family attorney Ben Crump said the 2021 investigation plus the exoneration of the two falsely convicted and imprisoned men shows how NYC authorities and federal agencies “had factual evidence, exculpatory evidence that they fraudulently concealed from the men who were wrongfully convicted for the assassination of Malcolm X.”

“It’s not just about the triggermen,” Crump said. “It’s about those who conspired with the triggermen to do this dastardly deed.”

Mr. Crump said they are alleging the NYPD, CIA and FBI conspired to murder Malcolm X.

“That is what we are alleging, yes,” said Mr. Crump at the news conference. “They infiltrated many civil rights organizations.”

Federal law says that there is no statute of limitations for murder, manslaughter, sexual assault, or terrorism crimes. There is a seven-year statute of limitations for a charge of bribery of a government official, official misconduct, and other related offenses.

The exonerated men, who spent decades in prison for a murder they did not commit, received a $36 million settlement.

Malcolm X was 39 when he was assassinated in 1965 at the Audubon Ballroom, which is now a memorial to the slain civil rights leader.