Conspiracy theories have surrounded John F. Kennedy's death since the beginning. Did Lee Harvey Oswald act alone? If someone else was involved, who was it?
"There's too many unanswered questions and they've been left go for so many years that they're part of the popular mindset," said David Longenbach, lecturer of history at Penn State Lehigh Valley.
Many people have an opinion on the assassination and whether there was a conspiracy.
"I feel like we're really not going to know the answer in our lifetime" said Debbie Zuech-Smyrl.
"I don't think it's the government covered it up, but I think Oswald was blamed for the whole thing even though it could have been a group of other people, said Bryan Puskas.
"The discussion of multiple shooters is always a big one," said Longenbach. "Did Oswald, was he the only one to pull the trigger? Were there additional shooters on the grassy knoll?"
"Johnson of course had a rocky relationship with the Kennedys. How much did he know? One of the famous photographs is Air Force One with Jackie there. Was he really involved somehow?"
A Gallup poll finds 61 percent of Americans believe others were involved in the assassination. The Mafia and the federal government are the most common answers, followed by the CIA and Fidel Castro or Cuba.
"There were certain issues between the Kennedy family and the Mafia, but it was not conclusively proven that (Jack) Ruby was in fact a Mafioso or connected to organized crime in any way," Longenbach said.
Even in the days immediately following President Kennedy's death, Gallup found 52 percent of Americans thought other people were involved in a conspiracy.
"I think there's always going to be that doubt in the back of everyone's mind that they're waiting for that untold story to surface and really give them the closure that they're looking for," said Longenbach.
According to Gallup polls taken over the years, the majority of Americans have always thought other people were involved, except in 1966 when it was split down the middle.