Killing of JFK: The story that will never die IT TOOK only a split second for the bullets from the assassin's rifle to reach their intended target. Yet the echoes from the shots that killed John F Kennedy have now reverberated across the United States for exactly 50 years as the nation marks today's anniversary of one of the darkest chapters in its history. Memorial services are planned across the country to remember the youthful and charismatic president who was cut down at the age of just 46 as he was driven through Dallas in an open-topped limousine, his loyal and equally popular young wife Jackie by his side. Today's services are the culmination of a week-long remembrance of the events of 22 November 1963, with every aspect of the shooting, and Lee Harvey Oswald Oswald's death at the hands of Dallas nightclub owner Jack Ruby two days later, analysed during a sea of television specials. Presidents Barack Obama and Bill Clinton laid wreaths at Kennedy's grave in Virginia on Wednesday accompanied by Ethel Kennedy, the widow of John F Kennedy's brother Robert, who was assassinated in 1968. Excerpts of Kennedy's speeches will be read today during a service at Dealey Plaza, Dallas, followed by a concert by the US Naval Academy men's choir. The city's Texas Theatre, where Oswald was arrested within hours of Kennedy's death, and after he murdered Dallas police officer J D Tippit during his getaway, will screen War is Hell, the film shown on that day. There will also be a musical tribute at Kennedy's presidential library and museum in Boston, and a mass at St Matthew's cathedral in Washington DC, where his funeral took place. In addition, a minute's silence will be observed at 1pm in cities across the US, marking the time Kennedy's death was confirmed. But through numerous conspiracy theories and government inquiries, blockbuster movies and popular fiction, the mystery of JFK's killing has endured for decades. "It's a story without an ending," said Lamar Waldron, author of the new book The Hidden History of the JFK Assassination and a prominent historian regarded as a leading experts on the shooting. The most recent government inquiry [the 1978 House Committee on Assassinations] called it a conspiracy and the National Archives refuses to say how many files from the investigations remain unreleased. It lacks a resolution, and that's one reason there's still so much interest today. A Gallup poll this week to coincide with the anniversary reported that 61 per cent of Americans did not believe that Oswald, the man named in 1964 by the official Warren Commission report into the assassination as the lone gunman, acted alone. In fact, according to Victor Bugliosi, author of another new JFK book entitled Reclaiming History, conspiracy theorists have, over the years, accused no fewer than 42 groups, 82 assassins and 214 individuals of being involved in various plots. Suspects have ranged from the Mafia, the Russian KGB and Cuban president Fidel Castro to the CIA, leaders of the US oil industry and Kennedy insiders, including vice-president Lyndon B Johnson and even Jackie Kennedy herself, acting out of revenge for her husband's philandering. As for the fatal shots, they were fired by Oswald from the sixth-floor window of the Texas School Book Depository, by a mystery shooter or shooters on the now-famous grassy knoll at Dealey Plaza where Kennedy met his end, or by some combination of the two. This week John Kerry, the US secretary of state, became the latest big-name politician to question the official version of events, saying: "To this day, I have serious doubts that Lee Harvey Oswald acted alone. I certainly have doubts that he was motivated by himself. "Kudos to John Kerry for saying this," Waldron said. He's only the most recent US official to believe Cuba had something to do with it. Releasing all the JFK assassination files is important because US-Cuba relations have been essentially frozen since. In his book, Waldron points the finger at 1960s Mob bosses and CIA "assets" Carlos Marcello and Santo Trafficante, in association with agency associates, and says there are probably millions of documents, tapes and transcripts still being withheld by the CIA and Naval Intelligence. In 1992, Congress passed the JFK Act requiring their release after a national debate prompted by director Oliver Stone's controversial movie JFK. The 1991 film expounded the conspiracy theory and attacked the Warren Commission's so-called "magic bullet" explanation that a single shot from Oswald passed through Kennedy's neck and wounded the Texas governor John Connally sat directly in front of him. Marcello was identified by the 1978 congressional inquiry as having the "motive, means and opportunity" to have Kennedy killed. But Waldron, whose 25 years of research included interviews with dozens of Kennedy associates and former FBI, Secret Service, military intelligence agents and senior politicians, insists it was not just a Mafia plot. "The press loves to pigeonhole [the theory] into "the Mafia did it" box, but the Mob could not have pulled it off, couldn't have killed JFK and just got away with it without the help of at least three people in the CIA," he said.