Civil rights attorneys and Malcolm X's daughters revealed on Saturday new evidence that they said indicates the NYPD and FBI conspired in the assassination of the civil rights activist in Washington Heights 56 years ago to date.

In a letter written on his death bed, former undercover police officer Ray Wood confessed that he was tasked with infiltrating civil rights organizations and ensuring that Malcolm X's security guards were arrested days prior to the activist's assassination.

"My job was to infiltrate civil rights organizations throughout New York City, to find evidence of criminal activity, so the FBI could discredit and arrest its leaders," Wood wrote in a letter dated January 25th, 2011. "Under the discretion of my handlers I was told to encourage leaders and members of civil rights groups to commit felonious acts."

Wood admitted in the letter to deliberately pressuring Malcolm X's two security guards to plot to bomb the Statue of Liberty in order to get them arrested. In 1965, one of the defendants, Walter Bowe, testified the plot was Wood's idea, according to a NY Times report at the time. Bowe and Khaleel Sayyed were "key players in Malcolm X's crowd control security detail," Wood wrote. The two were arrested by the FBI days before Malcolm X was assassinated at the Audubon Ballroom on February 21st, 1965. Their arrest kept them from running security at the ballroom.

"Thomas Johnson was later arrested and wrongfully convicted to protect my cover and the secrets of the FBI and NYPD," Wood wrote. Johnson, also known as Khalil Islam and previously, Thomas 15X Johnson, spent more than two decades in prison and maintained innocence until he died in 2009.

In the letter, Wood says he tried to resign, but was threatened with arrest for marijuana and alcohol trafficking if he did not complete his assignments.

The letter was revealed at a press conference on Saturday with Malcolm X's three daughters, Qubiliah Shabazz, Ilyasah Shabazz and Gamilah Shabazz; civil rights attorneys Ben Crump, Ray Hamlin, and Paul Napoli; and Wood's cousin, Reggie Wood.

During the press conference, Wood said his cousin felt "forced to betray his people."

"This letter helps me to understand the pain and guilt that Ray felt for the last 55 years," the younger Wood said. "He wanted the world to know that he is deeply sorry. I hope that this information helps the Shabazz family to more clearly understand what happened to their father on that horrible day."

Ilyasah Shabazz, one of Malcolm X's daughters, said any evidence should be investigated.

"There has always been uncertainty about all of the facts surrounding the assassination of my and my five sisters' father," Shabazz said. "Any evidence that provides greater insight into the truth behind that terrible tragedy should be thoroughly investigated."

Last year, Manhattan District Attorney Cy Vance's office was conducting a preliminary review that could lead to potential investigative steps after Netflix aired a documentary reviewing evidence of the assassination. The documentary looked at evidence that Johnson and Norman 3X Butler, who is now Muhammad Abdul Aziz, were innocent. Aziz, now 81, maintains his innocence.

DA Vance's spokesperson Danny Frost said Sunday that the district attorney's "review of this matter is active and ongoing."

A spokesperson for the NYPD, Detective Denise Moroney, said in a statement: "Several months ago, the Manhattan District Attorney initiated a review of the investigation and prosecution that resulted in two convictions for the murder of Malcom X. The NYPD has provided all available records relevant to that case to the District Attorney. The Department remains committed to assist with that review in any way."

The FBI declined to comment.

This article has been updated to correct where Malcolm X was assassinated. He was killed in Washington Heights, not Harlem.