Warren Commission exhibit CE399--the “single” or “magic” bullet. Photo from the National Archives and Records Administration. ARC: 305144. This image is in the public domain according to terms of Title 17, Chapter 1, Section 105 of the US Code. (Via Wikipedia)Who shot John F Kennedy has been one of our country's most enduring mysteries.

But back In 1979, FBI expert Dr. Vincent P. Guinn provided open-and-shut evidence that confirmed the single bullet theory, and that there were only two bullets fired. If not for his testimony, the presence of a second shooter that November day in Dealey Plaza would have been much harder to deny.

“There is no evidence for three bullets, four bullets, or anything more than two, but there is clear evidence that there are two,” Guinn testified before the Committee on Assassination. 

After further studies, however, researchers are now saying that Guinn’s analysis was “fundamentally flawed” in a new video by American Scientist released this week.

Using the same technique, researchers analyzed similar bullets, in an attempt, to see how chemically different the bullets might be from one another. The research was then used to determine how definitively chemical analysis could be used to rule out other possible bullets and shooters.

According to the study, one of the 30 bullets analyzed by a team from Texas A&M University, matched an assassination bullet, chemically, meaning the findings in 1979 report were much less specific then experts believed, and testified to, at the time.

Clifford Spiegelman of Texas A&M University was one of the lead authors of the study. “So according to Dr. Guinn's testimony that the bullets used in the murder were chemically unique,” Spiegelman told American Scientist, “we must have been involved in the Kennedy assassination since we have fragments that match.”

Watch the interview with Dr. Clifford Spiegelman:

His team used the same technique that experts for the FBI back in the '70s, like Dr. Guinn, used—neutron activation analysis. This process is used to determine the elements found within a material, such as lead from the bullet fragments. Using radioactive decay, researchers can analyze the spectra of the radioactive emissions, which are well-known to science, then determine the exact concentration of elements found within the material, according to Wikipedia.

“The bullet components of the JFK assassination study were seriously messed up,” Spiegelman said in a recent Youtube interview. “It was not understood that the investigation should have been multi-disciplinary and not just chemical.”

If Spiegelman is right, there is no way to rule out a second shooter, on chemical analysis alone. Therefore, the 1979 report is fundamentally flawed.  

Four chemicals were analyzed in the assassination report: antimony, copper, arsenic and silver.  FBI experts testified that if a bullet had the same chemical composition as another bullet, both bullets would logically have come from the same source, and likely the “same box” of ammunition--a liklihood that most experts today believe is completely overstated.

Read more: 3-D Digital Forensic Analysis Confirms Lee Harvey Oswald Photo

According to the 1979 Committee on Assassinations investigation, the chemical analysis of the bullet fragments found after the assassination proved there could only have been two bullets—likely meaning Oswald was the one and only shooter. “The neutron activation analysis further supported the single bullet theory by indicating that there was evidence of only two bullets … analysis showed no evidence of a third bullet among those fragments large enough to be tested,” according to the authors of the report.

Spiegelman maintains he is not purporting the existence of a second shooter, only that the testimony used to come to the conclusion that the bullet fragments came from only two bullets—meaning that there could not have been a second shooter—is scientifically unsound.