On the morning of February 21, 1965, Malcolm X woke up, alone, in a room at New York City's Hilton Hotel.

He was, literally, a man without a home. One week earlier, his house in the East Elmhurst section of Queens had been firebombed in the middle of the night. His wife, Betty Shabazz, and their four young children emerged unscathed, though they were now staying at the home of friends in an undisclosed location for their safety.

Malcolm strongly believed that his former colleagues from the Nation of Islam (NOI), under the leadership of Elijah Muhammad, were behind the firebombing. Once the second-most powerful member of the religious and political movement, he now found himself looking over his shoulder at the militant Muhammad loyalists he knew could easily snuff out his life.

As he told reporters around that time, "I live like a man who is dead already."

Malcolm X left the Nation of Islam after his comments about President Kennedy’s death

The Nation of Islam, with its focus on Black empowerment, had provided a lifeline for the man still known as Malcolm Little during his incarceration for larceny in the late 1940s. Following his parole in 1952, the former street hustler assumed increasingly important roles under Muhammad's wing, becoming minister of Boston Temple No. 11 and then Temple No. 7 in New York City.

A towering figure of intimidating intellect, the fiery Malcolm X helped make the Nation of Islam an intriguing alternative to African Americans who remained unconvinced by the nonviolent demonstrations of Martin Luther King Jr. and the Southern Christian Leadership Conference. But he eventually found himself at odds with NOI leadership for his public revelation of Muhammad's adulterous affairs, as well as the perceptions that his individual power had become too dangerous.

After Muhammad suspended him for saying that President John F. Kennedy's assassination was the result of "chickens coming home to roost" in a violent society, Malcolm X left the movement in March 1964, his turn toward a more inclusive form of activism and denunciations of the NOI further fueling the animosity between the two sides.

READ MORE: Martin Luther King Jr. and Malcolm X Only Met Once

Malcolm X was shot while on stage during an Organization of Afro-American Unity meeting

On that cold February day, nearly one year after his split from the NOI, Malcolm X checked out of his hotel room and headed to the Audubon Ballroom in northern Manhattan for a meeting of his newly founded Organization of Afro-American Unity.

As recalled in the book Malcolm X: The Assassination, the normally unflappable activist was unusually agitated that day, the toll of recent events perhaps weighing heavily on his mind. He snapped at an aide after learning the guest speaker had canceled, and sent his chief lieutenant, Benjamin 2X, to deliver introductory remarks.

Malcolm X took the stage himself just after 3 p.m., but a greeting was barely out of his mouth when a commotion ensued a few rows back and someone yelled: "Get your hand out of my pocket!"

Malcolm X exhorted them to "be cool" as his bodyguards focused on the scuffle, clearing the path for a man to pull out a sawed-off shotgun and blast the unprotected speaker in the chest, knocking him backward over a set of chairs.

In the front row, a pregnant Shabazz shielded her four children as two more men charged the stage, pistols firing. The ensuing pandemonium gave them some headway for an escape, though one of them, 22-year-old Talmadge Hayer, was significantly slowed after getting shot in the leg and badly beaten by the crowd outside.

Meanwhile, Malcolm X was rapidly fading from the dozen-plus bullets pumped into his body. Supporters got him onto a stretcher and into the Columbia Presbyterian Medical Center across the street but attempts to revive his heart failed, and he was declared dead at 3:30 p.m.

There is still much debate over who killed Malcolm X

Although the Nation of Islam denied any involvement in the shooting, authorities focused on NOI suspects and soon apprehended Thomas 15X Johnson and Norman 3X Butler, their presence at the Audubon Ballroom allegedly confirmed by eyewitnesses. Hayer, Johnson and Butler were convicted of first-degree murder in March 1966 and were sentenced to 20 years to life in prison.

However, this was hardly an open-and-shut case, as the evidence tying Johnson and Butler to the crime scene was thin. During the winter of 1977-78, Hayer signed an affidavit in which he cleared the men convicted at the trial and named four other accomplices, though a judge determined that this was not sufficient cause to reopen the case. (Johnson and Butler were granted parole the following decade, while Hayer left prison in 2010).

Over the years, more complexities emerged as declassified documents revealed the extent to which authorities were tracking Malcolm X and the mysterious lack of a police presence at the Audubon Ballroom on that fateful day. Even after the alleged primary shooter was revealed by a blogger in 2011, his name repeated in the exhaustively researched book Malcolm X: A Life of Reinvention that same year, the FBI refused to reconsider the evidence for another investigation.

More than 50 years onward, the memory of Malcolm X remains tied to that of his great rival, Dr. King, their words and symbolism enduring even as the true stories behind their assassinations seemingly remain shrouded in mystery.

Police officers remove the body of Malcolm X from the Audubon Ballroom after his fatal shooting just before a speech on February 21, 1965, in Harlem, New York