Almost all of the remaining classified documents concerning the assassination of John F Kennedy will remain secret for now, despite a deadline for their release passing on Friday (NZ time).
The US President, commonly known as 'JFK', was shot dead on November 22, 1963, as his motorcade passed through Dallas, Texas. Officially, he was shot by lone gunman and ex-US marine Lee Harvey Oswald, who was himself shot two days later by nightclub owner Jack Ruby.
In 1992, the US passed the President John F Kennedy Assassination Records Collection Act, which mandated all government records concerning the assassination be released 25 years later - October 26, 2017 (US time).
The law, passed in the wake of Oliver Stone's controversial JFK movie, said documents could only be kept secret after this date if "continued postponement is made necessary by an identifiable harm to the military defense, intelligence operations, law enforcement, or conduct of foreign relations; and (2) the identifiable harm is of such gravity that it outweighs the public interest in disclosure".
Present US President Donald Trump had indicated he wouldn't block any of the 35,000 documents from release, but as the deadline approached, he said he had "no choice".
"Executive departments and agencies have proposed to me that certain information should continue to be redacted because of national security, law enforcement and foreign affairs concerns," he said in a memo.
"I have no choice - today - but to accept those redactions, rather than allow potentially irreversible harm to our nation's security."
About 2800 documents will be released, while the rest - some of which have been previously released in redacted form - will sit on ice for another six months, after which Mr Trump says he'd like them made public. The CIA and FBI reportedly made most of the requests to withhold the documents.
It's not known what the documents, set for release on the US National Archives website, will reveal, but Mr Trump has tweeted they are "so interesting".
Mr Trump is promsing the documents being withheld from release this week will eventually be made public except in the "rarest cases".
Oswald insisted he was a "patsy" and had no part in the shooting. A 1988 New York Times poll found only 13 percent of Americans believed he acted alone and a 2003 ABC News poll found 70 percent believed there was, at the very least, a wider plot.
More recent polls have found similar levels of scepticism regarding the official story.
So who was behind it, if you believe the conspiracies?
- The mafia: JFK allegedly had ties to organised crime, as did Ruby, whose conviction for killing Oswald was overturned, but he died before a retrial could be held.
- Ruby had asked repeatedly to speak to officials investigating the President's assassination, saying: "I want to tell the truth and I can't tell it here." He was denied that chance.
- The CIA: JFK reportedly wanted to cut the spy organisation's budget considerably. The CIA is also believed to have considered JFK weak on communism and held a grudge over his failure to give the failed Bay of Pigs invasion of Cuba any air support.
- The KGB: Oswald, a Marxist, had defected to the Soviet Union a few years earlier. Was he the killer, but under orders from the KGB?
- A second shooter: An official 1979 investigation into the assassination concluded there was probably a second shooter, perhaps situated on the famed 'grassy knoll'. It may have just been a coincidence that two assassination attempts were taking place at the same time.
- The FBI: Another theory states the FBI was aware of threats made on JFK's life by organised crime figures and deliberately failed to give him adequate protection.
- The Secret Service: An agent can be seen in the infamous 'Zapruder film' of the motorcade speeding away from the scene immediately after the shots ring out, contrary to what you'd expect. Another theory states two shots were fired accidentally by an agent travelling in a car behind JFK, taken by surprise when Oswald began shooting.
- Vice President Lyndon Johnson: Some say the man who'd ascend to the presidency after JFK's death knew of plots to kill him and brought them together to come up with a plan.
- Israel: Others believe JFK's opposition to Israel's nuclear programme was behind the assassination, with former Libyan dictator Muammar Gaddafi among them.
- The Kremlin: Another theory is Soviet leader Nikita Khruschev wanted revenge on JFK, after being forced to back down during the Cuban missile crisis.
- Cuba: If anyone had a motive to kill JFK, it was Cuban revolutionary leader Fidel Castro, who's believed to have survived hundreds of attempts on his life, many during JFK's tenure. President Johnson subscribed to this theory, saying in 1968: "Kennedy was trying to get to Castro, but Castro got to him first." Castro denied it, saying it would have been "absolute insanity".
- The military-industrial complex: JFK is said to have been planning to wind down US involvement in southeast Asia. The Vietnam War had already raged five years, when JFK became President, but the US were yet to get heavily involved. War is good for the arms business.
- The umbrella man: Photographs of the motorcade show a man holding an open umbrella, despite the fine weather. It's suggested it could have fired a dart - James Bond-style - at the President or perhaps signalled to a gunman when to shoot. In 1978, Louie Steven Witt testified he was the umbrella man and he'd brought it along to heckle the President. He told officials, if there was a Guinness World Record for being in the wrong place at the wrong time, he'd be number one "without even a close runner-up".
- Ted Cruz's father: Mr Trump has suggested that the father of former presidential rival Ted Cruz was involved in the assassination. Mr Cruz has called the claim "beyond ridiculous", but is looking forward to the documents proving that.