While the nation was still mourning the death of President John F. Kennedy, Frank Dyer was secretly working in a room at Oak Ridge National Laboratory to help solve the young president's murder.
Before him lay lead fragments from the bullets that had cut down the president and paraffin casts made from the hands and face of the suspected assassin, Lee Harvey Oswald.
The secretive, behind-the-scenes work that Dyer and fellow Oak Ridge chemist Juel Emery would carry out in the Tennessee laboratory over the next five weeks remains, even half a century later, one of the lesser-known chapters of the investigation into the Kennedy assassination.
With an FBI agent watching his every move, Dyer huddled over a table and used a small pair of tweezers to carefully remove tiny specks of gunpowder residue from the paraffin casts. Then, he and Emery analyzed the residue and the bullet fragments using a technique called neutron activation analysis to test two FBI theories: That the three bullets fired at the presidential limousine had come from the same weapon and that Oswald was the one who pulled the trigger.
Their analysis of the lead fragments would conclude that the bullets had indeed been fired from one weapon, the Italian-made, 6.5mm Carcano rifle used in the assassination. The tests on the gunpowder residue would prove inconclusive, mainly because the Dallas Police Department had mishandled the paraffin casts, tainting the evidence.
Regardless, the scientists' work was considered significant enough that it would merit a mention in the Warren Commission's 26-volume, 888-page final report on the presidential assassination.
"I've thought about that work a lot since then," Dyer, now 82, said recently from the living room of his Knoxville home.
With the 50th anniversary of the Kennedy assassination coming up Friday, the investigation into the president's death remains the object of distrust and skepticism among conspiracy theorists and other doubters who question the Warren Commission's finding that Oswald was the lone shooter.
Dyer believes his and Emery's work still holds up.
"No matter whether you're a PhD radiochemist like I was or if you're a gardener growing tomatoes or ... if you're an engineer putting something together, you can often see how you should have done (things) that you didn't do," Dyer said. But, "I think we did the best we could."
Dyer and Emery were pulled into the investigation just days after Kennedy was gunned down in Dallas on Nov. 22, 1963.
About a week after the assassination, their boss, William Lyon, was called to Washington for a secret meeting with the FBI. Investigators needed Oak Ridge's help in analyzing evidence from the assassination because the lab was one of the few places in the country with the facilities and the scientists to preform neutron activation analysis, a technique that was sometimes used in solving crimes.
The bullet fragments and the paraffin casts taken from Oswalds' hands and face were sent to Oak Ridge for testing.
An FBI chemist, Jack Gallagher, came to Oak Ridge to oversee the analysis.
For the next five weeks, Gallagher remained at Dyer's and Emery's side while the scientists pored over the evidence. "Jack took all of the notes and helped decide what we would do," recalled Dyer, who said the scientists were not allowed to keep notes of their own.
To get a better understanding of how gunpowder residue is scattered when a weapon is fired, Dyer and Emery went out to the Oak Ridge firing range, shot guns belonging to one of the laboratory's guards, and then made paraffin casts of their own hands. The FBI conducted its own experiments, even firing test rounds from Oswald's rifle.
The FBI was trying to find out if there was more than one kind of lead in the bullet fragments taken from the presidential limousine, which could mean there was more than one shooter. In the tests, the fragments were fed into an isotope reactor, causing the elements in the lead to emit gamma rays that could then be analyzed.
By analyzing the ratio of barium and antimony in the bullet fragments, Dyer and Emery were able to conclude that the bullets came from the same batch of ammunition and were fired from the same rifle.
"All of the pieces that we analyzed were so similar, there didn't seem to be that much of a chance that there was any lead from any other bullets," Dyer said.
The tests on the gunpowder residue removed from the paraffin casts posed a more complicated problem.
While the FBI had the rifle used in the assassination, investigators still needed to prove that Oswald had fired the weapon. To do that, the Dallas Police Department made casts of Oswalds' hands and face by covering them with molten paraffin. Once the paraffin hardened, the casts were peeled off, taking with them whatever gunpowder residue was present on Oswald's body.
But there was a problem. Forty-five minutes after Kennedy was assassinated, Oswald shot Dallas Police Officer J.D. Tippit. What's more, a Dallas police officer had taken the casts
home as a souvenir, tainting the evidence.
By the time the casts arrived at Oak Ridge for testing, residue was smeared on both sides. The mishandled evidence made it impossible for the chemists to distinguish between residue fired from the rifle that killed Kennedy and the revolver used to kill Tippit. Thus, the tests were inconclusive.
"This five weeks of study," Lyon would later note, "shows what every analytical chemist knows: That bad samples plus good work equals wasted time."
To thank Dyer and Emery for their work, an FBI agent gave each of them an unusual memento: A bullet casing fired from Oswald's rifle during the post-assassination tests. Dyer still has the casing, which he keeps in a medicine vial.
"I used to just keep it in a drawer," Dyer said, holding the oblong cartridge up to the light for closer inspection. "I never did think that much about it. I didn't think it had much value. But it's kind of a keepsake."
(Contact Scripps Howard News Service reporter Michael Collins at firstname.lastname@example.org)