On Friday, Nov. 22, Americans will memorialize the 50th anniversary of the assassination of President John F. Kennedy. However, a new Gallup Poll reveals that even a half a century later, most Americans refuse to believe that Lee Harvey Oswald was Kennedy's lone killer.

Evidence shows that 61 percent of Americans believe that JFK's death is immersed in a secret conspiracy involving either the Mob, the government (including the CIA), Cuba or Russia amongst other theories.

"The Kennedy assassination was a watershed moment in American life... the first president to be killed in the era of film and television. With numerous photos of JFK taken in his last moments alive, including the infamous "Zapruder film" showing Kennedy in the moments before, during, and after he was struck, Americans have long speculated not only about why the shooting occurred, but also how it happened," states Gallup.

Could one man have fired three shots and killed Kennedy in a way consistent with his wounds? If Oswald actually acted alone at the Texas School Book Depository, was he funded or supported by others? These are some of the questions that have burned in the American psyche since that fateful day in 1963.

Although there are a number of conspiracy theories, one of the most popular is that President Lyndon B. Johnson was involved in Kennedy's death.

"A lot of Texans didn't like Johnson -- they thought he was a crook -- so as a result, they started creating this fiction after the assassination where he wanted Kennedy out so he could be president," said Dave Perry, who has been actively researching JFK's murder for nearly three decades and has published numerous articles on his investigation.  He continued telling CNN, "But we've found no evidence."

There are also claims that Kennedy was going to pull American troops out of Vietnam despite the military's wishes to send more troops to war. However, Perry say that the president talked about trying to resolve the situation, but he never made a claim that he was going to pull out of the country.

There is also hearsay that at least three different Mob groups did this independently and that Oswald had help.