This much we can stipulate: President John F. Kennedy was assassinated on Nov. 22, 1963, struck by two bullets — one in the head,  one in the neck — while riding in an open-topped limo through Dealey  Plaza in Dallas. Lee Harvey Oswald was charged with killing him, and a presidential commission headed by Chief Justice Earl Warren found that  Oswald acted alone.

That conclusion hasn't passed muster with the public. A 2003 ABC News poll found that 70% of Americans believe Kennedy's death was the result of a broader plot. We also conducted our own poll; in 2023, we asked everyone who joined our JFK Tour if they thought Oswald acted alone. Not surprisingly, 83% of the 6200 participants indicated a different conclusion to the Warren Report findings.

The trajectory of the bullets, some say, didn't square with Oswald's perch on the sixth floor of the Texas School Book Depository. Others suggest a second gunman —  perhaps on the grassy knoll of Dealey Plaza — participated in the shooting. Others believe in an even broader conspiracy. Was Kennedy killed by CIA agents acting either out of anger over the Bay of Pigs or at the behest of Vice President Lyndon Johnson? By KGB operatives? Mobsters mad at Kennedy's brother for initiating the prosecution of organized crime rings? Speculation over one of history's most famous political assassinations is such a popular parlor game that most people have taken the rumors to heart: just 30% of those polled by ABC believe  Oswald carried out the killing on his own.

We discovered that the most persistent conspiracy theory among all the 2023 poll participants was the infamous "grassy knoll" and the alleged second shooter lurking behind it. Enthusiasts of the Kennedy assassination conspiracy theories may have been aware of this for some time, but for those whose exploration has been limited to Oliver Stone's "JFK" and the infamous magic loogie scene from "Seinfeld," here's an update

To recap briefly: In 1964, the Warren Commission determined that only three shots were fired — all directed at the President from the Texas  School Book Depository, all attributed to Lee Harvey Oswald's bolt-action rifle. That seemed to be the final word. (Or the beginning  of a thriving conspiracy theory industry.) However, in 1979, the House  Assassinations Committee conducted its own investigation. It concluded that a fourth shot, which missed its target, had indeed been fired from behind a white picket fence on that grassy knoll. Yet, in 1982, a special panel from the National Academy of Sciences (NAS) argued that this supposed fourth shot was merely random background noise, likely just static.

In 2001, JFK assassination researcher D.  B. Thomas published an article in Science and Justice, a quarterly journal from Britain's Forensic Science Society. The article claimed that the NAS study had significant flaws and supported the findings of the House committee.

The crux of the disagreement stems from the limitations of audio and video technology at the time; the well-known Zapruder film lacked sound, and the main audio recordings from that day came from Dallas police transmission channels, captured when a motorcycle officer accidentally left his microphone on. The House panel utilized filtering techniques available then to identify "audible events" within a 10-second window that could indicate gunfire, ultimately identifying four distinct sounds.

Conversely, the NAS, while reviewing the House committee's findings, analyzed two other recordings from the police radio channels used that day. By cross-referencing these incomplete recordings and the police responses, they concluded that the alleged shot from the grassy knoll occurred too late to be part of the actual shooting.

Thomas holds a different view. By analyzing another example of what he calls "cross talk," he concluded that the gunshot-like noise from the grassy knoll coincided precisely with the moment John F. Kennedy was assassinated. He calculated that there was over a 96 percent likelihood that a second shooter targeted Kennedy. Furthermore, Thomas asserts that the fourth shot was the one that ultimately claimed the President's life.

None of this gets to the really juicy conspiracy theory stuff, such as who the shooter on the knoll was and, most importantly, who he or she was working for. But it's certainly not doing Earl Warren's legacy any good.