On a street near Dealey Plaza, just yards from where President John F Kennedy was shot dead 40 years ago this month, I met a man who told me who really pulled the trigger.
To be precise, it was not one gunman who killed the 35th President of the United States on 22 November 1963, but rather four shooters working as a team and firing from different positions. Lee Harvey Oswald - the man officially blamed for Kennedy's death - was not among them. The poor, hapless fool did not even know there was a plot to kill the President.
That, at least, was the theory of Ron Rice, a self-confessed conspiracist and a member of staff at Dallas's Conspiracy Museum, an establishment dedicated to the promotion of unofficial theories relating to JFK's death and other government "cover-ups". "They set Oswald up, and if you look at the photographs of him, he thought [the charges] were a joke," says Rice, having outlined his theory involving three alleged gunmen who are now dead and one who may or may not be alive. "The funny thing is that when you start to tell people that he was not involved they can't handle it."
Forty years after JFK was assassinated as he passed along Elm Street in central Dallas on a bright autumnal day, the debate as to who killed the 46-year-old President and why remains as intense, heated and bitter as ever. Never mind that, as long ago as 1964, the Warren Commission - the official, government-appointed inquiry - concluded that there was no evidence of a conspiracy; never mind that in 1988 the Justice Department drew an end to further Senate inquiries; put aside the advances in scientific testing over the past 10 years that have allowed Oswald to be conclusively linked to the crime. For some people, the truth remains untold; worse, it has been actively covered up. Even now, surveys show that fewer than 50 per cent of Americans believe there was just one gunman.
One of the effects of this is that an entire industry has grown up surrounding the death of JFK, who was shot twice as his motorcade passed through Dealey Plaza, his wife Jacqueline in the seat beside him and the Governor of Texas, John Connally, and his wife Nellie in the seats in front.
The VIth Floor Museum, for instance, established in the Texas Book Depository from where the 24-year-old Oswald fired (or did not fire) the shots that killed the President is now Dallas's biggest tourist attraction, annually drawing up to 500,000 people fascinated by a crime that has forever tarnished the image of this sprawling city. Visitors pay $10 for a tour that takes them past the window around which Oswald build a "sniper's nest" of cardboard boxes and from where he took aim with his Italian-made Mannlicher-Carcano rifle (bought by mail-order for $12.78) and squeezed off three shots. They can also watch the black-and-white television footage of Oswald in turn being shot and killed two days later by Dallas nightclub owner Jack Ruby.
Elsewhere, self-appointed experts guide tourists around Dealey Plaza, lead them up the Grassy Knoll from where some claim the fatal shots were really fired, point out the white picket fence behind which, on photographs taken that day, a gunman can be seen standing in the shadows, if you squint and really, really imagine.
There are annual conventions in Dallas where people buy everything from bumper stickers to T-shirts, and there are sales on the internet of bootlegged copies of the "Zapruder" home-movie shot by the Dallas dressmaker Abraham Zapruder, which captured the assassination. In 1992, the .38-calibre Colt Cobra revolver with which Ruby killed Oswald was sold at auction for $200,000, while the new owner is now offering a so-called "limited edition" of 5,000 bullets fired from that weapon for $500 each. Ruby's hat fetched $12,100, while the coroner's tag that was placed around Oswald's toe after he was shot dead was sold for $6,000. His signature sells for more than that of JFK's.
And, of course, the impending anniversary - on Saturday - has provoked still more merchandise and exploitation, including a dozen or more new books, the release of a new set of letters from the President's wife and new photographs of the President's family, and any number of media retrospectives. Britain's relatively short-lived fascination with Diana, Princess of Wales pales by comparison.
But it is not just in these obvious ways that the death of JFK continues to do business. Intellectually, as well as at a more visceral level, the assassination and its shroud of uncertainty continue to grip the American psyche. "Part of it is television. You have someone kept alive at the age of 46, forever charming and charismatic," says Robert Dallek, a respected biographer of Kennedy. "But much more importantly, it is the sense of the unfinished life, the unfinished achievements and the hopes he inspired: the 'New Frontier', putting a man on the Moon, the Peace Corps... these things spoke to American ideals and we have not had a lot of them since. There was Reagan briefly, but JFK was the last inspirational President."
In this environment it is not surprising that there continues to be a seemingly endless flow of books on JFK's death. Among the most recent - timed to coincide with the anniversary - is From Love Field: Our Final Hours with President John F Kennedy, by Nellie Connally, the last surviving passenger of the Presidential limousine and the person who spoke probably the last words that Kennedy would hear as they passed the cheering crowds: "Mr President, you certainly can't say that Dallas doesn't love you."
Connally, now aged 84, believes that Oswald alone killed JFK (and wounded her husband - "A $15 gun and a scrambled-egg mind caused all that horror"). But most of the glut of publications do not agree. One that differs greatly from Connally's view is Blood, Power and Money: How LBJ killed JFK, by Barr McClellan, father of President Bush's spokesman Scott McClellan. It claims that Vice-President Lyndon Johnson, the man who was later sworn in as President on Air Force One even before it had been publicly announced that JFK was dead, ordered the assassination and orchestrated the cover-up.
"Are we going to face up to this?" McClellan asked me. "We have this really tough decision that we seem not ready to face. There was a conspiracy and most people want an answer."
One of the reasons such conspiracies continue to flourish - and McClellan's seemingly outlandish claim is, in fact, among the more sober that one uncovers in the conspiracy world - is that many of the details surrounding the shooting really do seem to point towards a broader conspiracy.
Gerald Posner - the author of the exhaustive Case Closed, which argues convincingly that Oswald alone was responsible - admits there is much about the shooting that seems suspicious. "This is not a case where the conspiracies appear groundless," he says. "In the Arab world there are theories abounding that 4,000 Jews got the call not to go to work on September 11 that are made up out of thin air, but this is not like that. There are plenty of reasons for people to believe in a conspiracy: you have a guy who spent time in Russia, who was interested in Cuba. And then he is shot two days later by a man who has low-level links to the Mob."
Likewise, there are details in the official version of the shooting that have been scientifically proven to be perfectly plausible that people still seem unable or unwilling to believe. How, people ask, could one 6.5mm bullet, the so-called "magic bullet", hit JFK in the back, exit through his neck and then strike Governor Connally in the right shoulder and exit through his chest? How could Oswald fire three shots in eight seconds - one shot missed - using a bolt-action rifle? And what about the angle he was said to have shot from? When I looked out of the sixth-floor window on a cold, grey morning last week, the line of fire was at least partly obscured by trees.
Then there are the myths about the shooting that, although they have long been proved false continue to circulate: that the route of the motorcade was changed at the last minute to bring JFK closer to the Book Depository; that crucial frames are missing from the Zapruder film; that a barely seen figure on the film, referred to as "the Badgeman", was the assassin, disguised as a Dallas police officer.
And there have been developments over the years that have given the conspiracists hope. When, for instance, it was revealed in the 1970s that the CIA had been plotting with the Mafia to try to kill Fidel Castro in the early 1960s, it gave life to a whole new rush of conspiracies.
"It's an unsolved crime and an unsolved political crime that has potential importance for our national security, the political process in the country and for suspecting that unseen forces are running the agenda of our country," said Jim Lesar, of the Assassination Archive and Research Centre (AARB) in Washington, a non-profit research group that has obtained many government documents relating to the shooting. Lesar believes there is more to the assassination than the public knows.
But in the absence of evidence to the contrary even those who tend towards conspiracy are left with just the facts. Gary Mack, curator of the VIth Floor Museum, says he believes there most likely was a gunman other than Oswald. But he adds: "The reality is that there is no hard evidence of anyone other than Lee Harvey Oswald being involved. There are holes in the story, but without hard evidence what can you do?"
Perhaps the stumbling block is less the lack of evidence than our unwillingness to accept that Oswald could have been responsible for Kennedy's death - for bringing to an end the now mythologised idealism. How could a confused and troubled loner be allowed to kill the most powerful man in the Western world?
In Case Closed, Posner quotes the historian William Manchester, who said: "Those who desperately want to believe that President Kennedy was the victim of a conspiracy have my sympathy. If you put the murdered President of the United States on one side of the scale and that wretched waif Oswald on the other side, it does not balance. You want to add something weightier to Oswald. It would invest the President's death with meaning... He would have died for something. A conspiracy would do the job nicely. Unfortunately, there is no evidence that there was one."
There is one person central to all of this who disagrees with the likes of Posner and Manchester and who in her own way is helping to keep the conspiracies alive. Having remarried decades ago, she now goes by the name of Marina Porter, but back in 1963 she was Marina Oswald, the beaten and abused Russian-born wife of the gunman.
She still lives in the Dallas area and, before I left, I drove the 40 or so twisting miles out to the bungalow she shares with her husband. It was he who answered the door and he who explained that she did not wish to speak. Apparently Oswald's ex-wife has now been persuaded that her former husband was not involved whatsoever.
In a 1996 letter she wrote: "At the time of the assassination of this great President whom I loved, I was misled by the 'evidence' presented to me by government authorities and I assisted in the conviction of Lee Harvey Oswald... I am now convinced that he was an FBI informant and believe that he did not kill President Kennedy."
She concluded: "It is time for Americans to know their full history."Reuse content