JFK assassination expert explains the 'embarrassing' secrets which might be revealed once Trump releases files

Donald Trump has ordered for documents on John F Kennedy's assassination to be declassified.

JFK was murdered in 1963 while riding in his open-top Lincoln Continental Presidential Limousine through Dealy Plaza in Dallas, Texas.

Less than two hours later, former US Marine Lee Harvey Oswald was apprehended by police and was charged with the then-president's murder.

President John F Kennedy was assassinated in 1963 (Bettmann / Contributor)

The National Archives and Records Administration has previously said 97 percent of the roughly five million pages in its collection are related to the JFK assassination, CBS News reports, and now ,Trump wants to unseal some — or possibly all — of the remaining documents.

The president signed an order on Thursday (January 23) ordering the director of national intelligence and attorney general to spend the next few days coming up with a plan to release the final files in question.

Part of the newly signed order states, as per Mail Online: "More than 50 years after the assassinations of President John F Kennedy, Senator Robert F Kennedy, and the Reverend Dr. Martin Luther King, Jr., the Federal Government has not released to the public all of its records related to those events.

"Their families and the American people deserve transparency and truth. It is in the national interest to finally release all records related to these assassinations without delay."

As to what is expected to be found in the documents, an expert has suggested that they could reveal some 'very embarrassing' secrets about the CIA.

Speaking to Fox News, Gerald Posner, the author of Case Closed: Lee Harvey Oswald and the Assassination of JFK, said: "I think that we could actually find the files that are very embarrassing to the CIA and one of the reasons they’ve held on to these for so long."

He went on to suggest that the CIA were aware of Oswald before he assassinated JFK, but the CIA let the Marine vet slip through the net.

"I think the CIA was surveying him," said Posner.

"They knew what he was doing. They knew he was unhinged, that he had taken out a pistol and slammed it on the table at the Soviet mission."

Gerald Posner is an American journalist and author (NBC News)

The order also relates to files on Martin Luther King Jr.'s assassination; something the late activist's family have spoken out on.

They said: "Today, our family has learned that President Trump has ordered the declassification of the remaining records pertaining to the assassinations of President John F. Kennedy, his brother Robert F. Kennedy, and our father, Rev. Dr. Martin Luther King, Jr.

"For us, the assassination of our father is a deeply personal family loss that we have endured over the last 56 years. We hope to be provided the opportunity to review the files as a family prior to its public release."

King was killed five years years after JFK's assassination.