Astonishing files were released on Thursday much to the glee of conspiracy theorists. President Trump tweeted plans to release them in full but back-pedalled under pressure from security agencies.
The additional documents will now be subject to a 180-day review to determine why they cannot be made available.
The explosive revelations thus far include Lee Harvey Oswald’s links to the Russian secret service, and several “hare-brained” schemes to murder Fidel Castro, the Cuban dictator.
Here’s what we know so far.
Lee Harvey Oswald overheard speaking “broken Russian” to KGB agent
JFK’s assassin Lee Harvey Oswald was intercepted speaking to a KGB officer in “broken Russian” two months before the murder.
A document says: “According to an intercepted phone call in Mexico City, Lee Oswald was at the Soviet Embassy there on 28 September 1963 and spoke with the Consul, Valeriy Vladimirovich Kostikov.
“This was learned when Oswald called the Soviet Embassy on 1 October, identifying himself by name and speaking broken Russian, stating the above and asking the guard who answered the phone whether there was ‘anything new concerning the telegram to Washington’.”
Oswald was a Soviet defector and Marxist, who lived in Belarus from 1959-1962. Such direct links with the KGB were previously unknown to the public, however.
Bizarre government plot to assassinate Castro
During 1963 various “harebrained” schemes were discussed to kill the Cuban Communist leader Fidel Castro, a 1967 document shows.
One involved giving him a contaminated diving suit that would infect him with a chronic skin disease, with tuberculosis bacteria in the breathing apparatus.
Even more strangely, there was a plan to booby-trap a seashell and plant it wherever Castro was set to go diving. The seashell would be so spectacular the Cuban president would not be able to resist picking it up.
That plan was dropped when authorities realised “there was no shell in the Caribbean area large enough to hold a sufficient amount of explosive which was spectacular enough to attract the attention of Castro”.
Warning about book accusing Bobby Kennedy of having lover Marilyn Monroe KILLED
Both Mr Kennedy and the director of the FBI received a letter warning of Frank Capell’s 1964 book, The Strange Death of Marilyn Monroe.
It claims Bobby Kennedy had the star killed when she threatened to expose their long-standing affair.
Mr Capell’s book claimed: “Miss Monroe’s involvement with Kennedy ‘was well-known to her friends and reporters in the Hollywood area’, but was never publicised.”
The book went on to theorise that Mr Kennedy, the brother of murdered president John F. Kennedy, “had Communists ‘murder’ Miss Monroe” when she threatened to go public with their affair.
Dallas policeman really killed Kennedy
One document claims Dallas police officer J D Tippit was JFK’s true killer.
The allegation was based on a conversation between an FBI informant and the Principal of Notre Dame University H. Theodore Lee, who had said members of a pro-Cuba group in Dallas had made the connection between Officer Tippit and the murder.
The policeman had reportedly been seen at a nightclub with Oswald in the weeks before the assassination.
Anonymous call tipped off British newspaper 25 minutes before shooting
A senior reporter at the Cambridge News received a phone call advising he contact the American Embassy in London for “big news”, before the caller promptly hung up.
MI5 claim this phone call happened 25 minutes before the president was shot as he drove through Dallas, Texas in an open-top car.