NEW YORK — Two of the three men convicted in the assassination of Malcolm X are set to be cleared Thursday after insisting on their innocence since the 1965 killing of one of the United States’ most formidable fighters for civil rights, their lawyers and Manhattan’s top prosecutor said Wednesday.

A nearly two-year-long re-investigation found that authorities withheld evidence favorable to the defense in the trial of Muhammad Aziz, now 83, and the late Khalil Islam, said their attorneys, the Innocence Project and civil rights lawyer David Shanies.

“The assassination of Malcolm X was a historic event that demanded a scrupulous investigation and prosecution but, instead, produced one of the most blatant miscarriages of justice that I have ever seen,” Innocence Project co-founder Barry Scheck said in a statement.

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 organization’s message at the time: racial separatism as a road to self-actualization. He famously urged Black people to claim civil rights “by any means necessary.”

At age 39, he was gunned down as he began a speech in Harlem’s Audubon Ballroom on Feb. 21, 1965.

Aziz, Islam and a third man, Mujahid Abdul Halim — also known as Talmadge Hayer and 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 was involved. The two, then known as Norman 3X Butler and Thomas 15X Johnson, maintained throughout that they were innocent and offered alibis at their 1966 trial. No physical evidence linked them to the crime.