The fifty years since the assassination of John F. Kennedy have done little to quell the public's interest or skepticism about who killed the president. In 1978 ... the House of Representatives Select Committee on Assassinations found that in addition to Oswald, there likely was a second gunman who fired at the president's motorcade. The commission concluded that the gunmen were part of a "conspiracy," without determining exactly who was behind it, opening the door to five decades and a cottage industry of theories. According to a 2003 ABC News Poll, 70 percent of Americans believe Kennedy's death was "the result of a plot, not the act of a lone killer." Fifty-one percent believe Oswald did not act alone, and 7 percent believe Oswald was not involved at all in the assassination. In the years since Kennedy's death more than 2,000 books have been written about the assassination, many of which espouse one or more conspiracy theories. In nearly every theory that involves American conspirators, be they wealthy industrialists or tough-as-nails mafiosi, one group is routinely represented - the CIA. One theory suggests that Oswald was a CIA operative and agents tampered with his FBI file before and after the investigation to make it appear he was a communist and lone wolf. [Another theory claims President Lyndon] Johnson was aided in the plot by another man who would become president, George H.W. Bush, a burgeoning CIA official who happened to be in Dallas on the day of the assassination.