JFK was shot dead by a sniper on November 22, 1962, and after more than 50 years, the US President is preparing to make the files about the assassination public.
But Dr Larry Sabato, a politics professor and author of ‘The Kennedy Half Century’, described why information about the murder may never be clear.
He told BBC News: “I think if you are looking long term, we will never find any document that really points us in the direction of anyone but Lee Harvey Oswald.
“That may be because Lee Harvey Oswald was the only assassin. It may also be because key documents were probably destroyed in the 1960’s and particularly the 1970’s when Congress took up where the warrant commission stopped.
“There were a lot of loose ends. Just to pick up on one of them, Jack Ruby. He was considered a hero at the time.
“Had he not shot Lee Harvey Oswald we would have gotten to the key question which was, ‘what was Oswald’s motive’? It still isn’t clear, it doesn’t make sense to most people who knew Oswald.
“We will never know because he was killed about 48 hours after the original assassination of president Kennedy.”
Dr Sabato was also critical of the Federal Bureau of Investigation (FBI) and Central Intelligence Agency (CIA) with the way the investigation was handled.
He said: “I don’t know if we will ever get to the bottom of all of this.
“I’m going to look at what the CIA and FBI really knew about Lee Harvey Oswald. They knew more than they told us, and they dropped the ball.
“This is not to criticise the current agencies, but it is to criticise the ones in the early 1960’s. We should have had a bean on Lee Harvey Oswald and the secret service should have known about him.
“They could only have known from the FBI or CIA and either agency ever told them about him.”
The National Archives will be releasing the JFK files later today where they will be available for download.
Some people believe the release may be delayed while President Donald Trump decides whether any of the files still need to remain classified if they pose a threat to national security.
Last weekend he tweeted: “Subject to the receipt of further information, I will be allowing, as President, the long blocked and classified JFK FILES to be opened.”
The release contains more than 3,000 files, each of which could contain hundreds of documents about JFK’s death.