National Archives makes public nearly 1,500 documents related to the US government's investigation into the 1963 assassination of president John F Kennedy.
US authorities have released thousands of secret files on president John F Kennedy's assassination, a case that still fuels conspiracy theories despite the official conclusion he was shot by Lee Harvey Oswald.
The CIA and FBI files released on Wednesday show US investigators spread their net wide and deep to find out if Oswald conspired with others in the November 22, 1963, murder that shocked the world.
Documents show they chased down myriad leads from Soviet intelligence to African communist groups and the Italian mafia.
They also show the extensive US efforts to spy on and influence the communist government of Fidel Castro in Cuba, which Oswald had contacts with and which Kennedy had sought to overthrow.
The 1,491 documents, many of them lengthy reports, were posted on the JFK Assassination Records page of the National Archives, which already has tens of thousands of record listings related to Kennedy's death and the investigation that followed.
Kennedy's assassination has long given rise to numerous conspiracy theories that do not accept the official verdict that Oswald worked alone when he shot Kennedy as the young president was rolling through the streets of Dallas, Texas in a convertible limousine.
Some believe Oswald, a communist sympathiser, was put up to it by Cuba or the Soviet Union.
Others believe that anti-Cuba activists, possibly with support in US intelligence or the FBI, had Kennedy killed.
And still, others believe his political rivals could have been at the root of the assassination.
QAnon embraced conspiracy theories
Philip Shenon, an expert in the Kennedy Assassination dossier, wrote in an article published by Politico on Wednesday that there are probably documents that will never be released for security reasons.
"So long as the government continues to keep some documents hidden, it will only further promote the idea that sinister conspiracies about Kennedy's death have a basis in fact," he said.
"Today, QAnon, which the FBI has deemed a domestic terrorism threat, has embraced JFK conspiracy theories," Shenon added, referring to the US conspiracy movement that has in recent years crept into the mainstream.
Shenon estimated that 15,000 assassination-related documents remain classified, most of them from the CIA and FBI.