JFK was not shot from grassy knoll site: study

The long-held conspiracy theory that former US President John F Kennedy was shot by a second gunman from the grassy knoll site is wrong, according to a new analysis of video footage of the shooting.

The results, published in the journal Heliyon, support the official autopsy findings that Kennedy suffered a gunshot wound caused by the same type of rifle as that owned by Lee Harvey Oswald, fired from the vicinity of the Texas School Book Depository building located behind the motorcade.

Kennedy was assassinated on November 22, 1963, while riding in a presidential motorcade at Dealey Plaza, in Dallas, Texas. Oswald was arrested shortly after the shooting.

A now widespread conspiracy theory posits that Kennedy was actually shot from a different location - the grassy knoll.

"The classified JFK files were recently released, and the fate of a few remaining files will soon be decided," said Nicholas Nalli, a senior research scientist at I M Systems Group, Inc. (IMSG) in the US.

"Given the current trendiness of news that are not based on facts, the study shows that thorough scientific investigation can make a difference in supporting one theory over another, and I therefore believe that the topic is as relevant today as it was nearly 55 years ago," he said.

There were several video recordings of the incident, and one in particular shows the shooting in detail.

A civilian bystander, Abraham Zapruder, filmed the motorcade with a 8-mm home movie camera, inadvertently recording an 8 second sequence of events that included a fatal gunshot wound to Kennedy in the head.

The Zapruder film shows the President's head moving back and to the left, which Nalli suggests was due to a recoil effect.

However, he also noted that observers had missed one vital part of the evidence: the forward head snap at the moment of the fatal bullet impact.

When analysed using fundamental classical mechanics, the forward head snap, which is visible in the Zapruder film, provides proof that Kennedy was shot in the head from behind.

"Rather than gloss over this fact, as has been done by most previous authors, including anti-conspiracy authors, I chose to study and model it explicitly," said Nalli.

He developed a simple one-dimensional gunshot wound dynamics model to explain the movements observed in the film.

The model makes explicit calculations of the forward head snap that occurred before Kennedy's head moved back and to the left after the gunshot.

To do this, the model uses known parameters from the crime scene, including bullet mass, speed, and diameter, camera shutter frequency and autopsy measurements.

This is the first time this aspect of the case has been considered so thoroughly and quantitatively.

The calculations show quantitatively that Kennedy's reactions after being shot in the head, as seen in the film, are physically consistent with a gunshot wound caused by a high-energy Carcano military rifle, the evidence rifle owned by Oswald.

The findings do not entirely rule out a conspiracy, but they do refute the most prominent theories that the fatal shot was fired from the grassy knoll.

They also oppose the idea that the Zapruder film proves a conspiracy - in fact, the opposite appears to be true, researchers said.