One might think, how could one unearth any new evidence about the assassination of John F. Kennedy at this point? 

There's been a lot of speculation over the years. We've reported on Robert F. Kennedy Jr.'s belief that the CIA was involved. He called it a "coup" and praised Tucker Carlson's coverage of information from a CIA insider on the matter.  

Yet, there's now a bit of a remarkable story courtesy of Paul Landis. Landis was a young Secret Service agent assigned to protect Jackie Kennedy, and he was standing on the running board of the follow-up car at the time of the assassination. So he was only about 15 feet away from the historic event when it occurred.  

After the shooting, it fell to him and agent Clint Hill to coax Jackie away from JFK's body so they could remove the mortally wounded president from the car and take him to the hospital. That was when Landis, now 88, says he saw something that has never been revealed before. 

As she did—standing up to follow Hill and another agent, Roy Kellerman, who lifted her husband’s body onto a gurney and raced into the hospital—Landis saw and did something that he has kept secret for six decades, he says now. He claims he spotted a bullet resting on the top of the back of the seat. He says he picked it up, put it in his pocket, and brought it into the hospital. Then, upon entering Trauma Room No. 1 (at that stage, he was the only nonmedical person in the room besides Mrs. Kennedy, and both stayed for only a short period), he insists, he placed the bullet on a white cotton blanket on the president’s stretcher.

Why has this not come out before? 

Landis left the Secret Service a few months after the assassination. He said he suffered PTSD and tried to suppress a lot of his memories because of that, that he had a recurring flashback of Kennedy's head exploding. So no one interviewed him, according to this report. He was never asked about the incident by the FBI or the Warren Commission, which seems incredible. He said he hadn't come to terms with it or started reading things on it until 2014. 

But this bullet now may upend the conclusions of the Warren Commission, and it raises a lot of questions. 

The "accepted" theory -- based on the available evidence before now -- was the "magic bullet" theory -- that one bullet passed through Kennedy's back, exited out his neck, and then hit Texas Gov. John Connally in the back, chest, hand, and thigh. Then another bullet was the one that hit Kennedy in the head. 

Now this new detail about where the bullet was found changes that theory. If this is true, it means it hit Kennedy in the back, somehow came out in the car, and never penetrated his body.

First, if the “pristine” bullet did not travel through both Kennedy and Connally, somehow ending up on Connally’s stretcher, then it stands to reason that Connally might have actually been hit by a separate bullet, coming from above and to the rear. The FBI recreation suggests that Oswald would not have had enough time to get off two separate shots so quickly as to hit Connally after wounding the president in the back. A second shooter must be considered.

And what about the bullet wound in the front of Kennedy’s neck? In one of the earliest critiques of the Warren Commission report, Josiah Thompson, author of Six Seconds in Dallas, proposed, not unreasonably, that the front-neck wound might have come from a bullet or bone fragment that was driven down and exited through the president’s throat from the final blast to his skull.

But there are other, darker explanations arising from the secrecy surrounding the X-rays and photographs taken at the autopsy and then not made public for decades. Jerrol F. Custer, the principal X-ray technician at the autopsy, testified in 1997 that there were several small metallic fragments in the cervical spine (the spinal region directly below the skull), which were visible in an X-ray, and that this was one of three X-ray exposures he took that night that went missing from the collection in the National Archives. This might have contained evidence of a shot from the front of the motorcade—a frangible bullet that disintegrated into tiny pieces after entry into the body. A heavy lift, for sure, but medical staffers who saw the front-of-the-neck wound before the tracheotomy believed it was an entrance wound because of its neatness.

Landis said he believed he had done the right thing by securing the bullet and then leaving it for what he thought would be the autopsy. He quit about six months later after failing to process it all, and he just assumed the Warren Commission had dealt with everything. After reading a book about the assassination in 2014, he then realized that the "pristine bullet" he had found was believed to have come out of Connally and that he needed to correct the record, and that's when he started talking to people about what he had found. He's also written a book, "The Final Witness."

James Robenalt, an Ohio-based lawyer and author of several books of history, has intensely researched the assassination and helped Landis work out his memories of that day. He believes Landis’ book will raise new questions about Kennedy’s death.

“If what he says is true, which I tend to believe, it is likely to reopen the question of a second shooter, if not even more,” Robenalt told The Times. “If the bullet we know as the magic or pristine bullet stopped in President Kennedy’s back, it means that the central thesis of the Warren Report, the single-bullet theory, is wrong.”

Which, he added, could mean that Connally was shot by a separate bullet and not by Oswald, whom he believes could not have reloaded fast enough.

That's pretty significant if it changes the whole accepted theory and comes not from speculation but from what seems like a credible witness.