NEW YORK, United States (AP) — Two men convicted in the assassination of Malcolm X are set to be cleared after more than half a century, with prosecutors now saying authorities withheld evidence in the civil rights leader’s killing, according to a news report yesterday.

The New York Times reported yesterday that Muhammad Aziz and the late Khalil Islam, who spent decades in prison for the crime, were being exonerated after a nearly two-year investigation by their lawyers and the Manhattan district attorney’s office. A court date is expected Thursday.

“These men did not get the justice that they deserved,” District Attorney Cyrus Vance, Jnr t,old the newspaper.

Vance tweeted that his office, the Innocence Project and a law firm would move to vacate the convictions, with more details to come Thursday.

One of the civil rights era’s most controversial and compelling figures, Malcolm X rose to fame as the Nation of Islam’s chief spokesperson, proclaiming the black Muslim organisation’s message at the time: racial separatism as a road to self-actualisation. He famously urged black people to claim civil rights “by any means necessary.”

He was gunned down as he began a speech in Harlem’s Audubon Ballroom on February. 21, 1965.

Aziz, Islam and a third man, Mujahid Abdul Halim — known at the time of the killing as Talmadge Hayer and later as Thomas Hagan — were convicted of murder in March 1966 and sentenced to life in prison.

Hagan said he was one of three gunmen who shot Malcolm X, but he testified that neither Aziz nor Islam were involved. The two, then known as Norman 3X Butler and Thomas 15X Johnson, maintained throughout that they were innocent.

“Thomas 15 Johnson and Norman 3X Butler had nothing to do with this crime whatsoever,” Hagan said in a sworn statement in 1977.

Hagan was paroled in 2010. He identified two other men as gunmen, but no one else was ever arrested.

According to The New York Times, the re-investigation found the FBI had documents that pointed to other suspects, and a still-living witness supported the alibi that Aziz has offered since his trial – that he was at home with a leg injury at the time of the shooting.

Also, the review found that prosecutors knew about but didn’t disclose that undercover officers were in the ballroom when the gunfire erupted, and police knew that someone had called the Daily News of New York earlier that day saying that Malcolm X would be killed.

“This wasn’t a mere oversight,” Deborah Francois, a lawyer for Aziz and Islam, told the Times. “This was a product of extreme and gross official misconduct.”

Aziz was released in 1985. He is now 83 years old.

Islam was released two years later and died in 2009.

The Manhattan district attorney’s office publicly acknowledged it was considering reopening the case after Netflix aired a documentary series last year, Who Killed Malcom X?, that explored a theory by scholars that the two men were innocent and that some of the real killers had escaped.