Single bullet theory

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The Single Bullet Theory was introduced by the Warren Commission to explain how three shots made by Lee Harvey Oswald resulted in the assassination of United States President John F. Kennedy.

CE399 side view

The theory, generally credited to Warren Commission staffer Arlen Specter (now a U.S. Senator.), posits that a single bullet, known as "Warren Commission Exhibit 399" (also known as "CE399"), caused all of the non-fatal wounds in both President Kennedy and Texas Governor John Connally. The fatal head wound to the President was caused by another bullet.

According to the single bullet theory, a one-inch long, copper jacketed, lead core 6.5 millimeter rifle bullet fired from the sixth floor of the Texas School Book Depository passed through President Kennedy’s neck, Governor Connally’s chest and wrist and embedded itself in the Governor’s thigh. In doing so, the bullet traversed 15 layers of clothing, 7 layers of skin, and approximately 15 inches of tissue, struck a tie knot, removed 4 inches of rib and shattered a radius bone. The bullet that is supposed to have done all this damage was found on a stretcher in the corridor at the Parkland Memorial Hospital in Dallas that the Warren Commission found was the one used by Governor Connally [12]. It became a key Commission exhibit, identified as CE399. Its copper jacket was completely intact. The bullet’s nose appeared normal, but the tail was compressed laterally on one side.

In its conclusion, the Warren Commission found "persuasive evidence from the experts" that a single bullet caused the President's neck wound and all the wounds in Governor Connally. It acknowledged that there was a "difference of opinion" among members of the Commission "as to this probability" but stated that the theory was not essential to its conclusions and that all members had no doubt that all shots were fired from the sixth floor window of the Depository building.

The 1978 House of Representatives' Select Committee on Assassinations agreed with the Single Bullet Theory but differed on the time frame. The Single Bullet Theory has been staunchly defended by those who believe the Warren Commission’s finding was correct and roundly criticized by those who disagree.

Number and sequence of the shots

Within minutes after the shots rang out in Dealey Plaza in downtown Dallas, Texas, at 12:30 p.m. on November 22, 1963, independent sources began reporting that three shots had been fired at the President’s motorcade. At 12:34 p.m., approximately four minutes after the shots were fired, the first wire story flashed around the world:

“DALLAS NOV. 22 (UPI) -- THREE SHOTS WERE FIRED AT PRESIDENT KENNEDY’S MOTORCADE TODAY IN DOWNTOWN DALLAS. JT1234PCS”

This report had been transmitted by United Press International reporter Merriman Smith from a radio telephone located in the front seat of the press car in the Presidential motorcade, six cars behind the President’s limousine. Smith’s communication with the Dallas UPI office was made less than a minute after the shots were heard, as his car entered the Stemmons freeway enroute to Dallas’ Parkland Hospital.

Merriman Smith’s dispatch was the first of many reports. There were dozens of journalists riding in the motorcade in three open press cars and a press bus, none of whom reported hearing a number of shots other than three. Photographers Robert Jackson and Tom Dillard riding in a car in the motorcade heard three shots. Dallas Morning News reporter Mary Woodward described hearing three shots as she stood in front of the Texas School Book Depository.

There has been some controversy over the number of shots fired during the assassination. The Warren Commission concluded that there were three shots fired. The vast majority of witnesses claim to have heard three, but there are some witnesses who could recall only 1 or 2 shots. A few witnesses thought there were four or more shots. Of 178 witnesses whose evidence was compiled by the House Select Committee on Assassinations (HSCA), 132 reported hearing exactly three shots, 17 recalled hearing two, 7 said they heard two or three shots (total: 88%). A total of 6 people said they thought they heard four shots, and 9 said they were not sure how many shots they heard. Another 7 people said they thought they heard 1, 5, 6, or 8 shots.

Governor Connally, riding in the middle "jump seat" of the President's limousine in front of the President recalled hearing the first shot which he immediately recognized as a rifle shot. He said he immediately feared an assassination attempt and turned to his right to look back to see the President. He looked over his right shoulder but did not catch the President out of the corner of his eye so he said he began to turn back to look to his left when he felt a forceful impact to his back. He looked down and saw a large amount of blood, and he knew that he was wounded—he thought fatally. He was pulled down by his wife, Nellie. Then he heard the third and final shot, which sprayed blood and brain tissue over them. [13].

Nellie Connally said she heard the first shot and saw President Kennedy with his hands at his neck reacting to what she later realized was his neck wound. After the first shot, she heard her husband yell, "oh, no, no, no" and turn to his right (away from her). Then she heard a second shot which hit her husband. She saw him recoil away from her and saw that he was hit. She immediately reached over and pulled him toward her into her arms and lay backward. Then she heard the third and final shot. Mrs. Connally said she never looked into the back seat of the car after her husband was shot. [14]

According to the Single Bullet Theory, one shot passed through President Kennedy's neck and caused all of Governor Connally's wounds (he was wounded in the chest, right wrist and left thigh), and one of the shots must have missed the limousine entirely. The Connallys never accepted the theory. While they agreed with the Warren Commission's conclusion that Oswald acted alone, they insisted that all three shots struck occupants of the limousine.

Location of back wound

Diagram of bullet's path from HSCA report

President Kennedy's death certificate places the bullet wound to Kennedy's back at the third thoracic vertebra.[15] The death certificate was signed by Dr. George Burkley, the President's personal physician. As interpreted by the House Select Committee on Assassinations Forensic Pathology Panel, the autopsy photos and autopsy X-rays show a bullet hole at the first thoracic vertebra. The bullet hole in the shirt worn by Kennedy [16] and the bullet hole in the suit jacket worn by Kennedy [17] both show bullet holes between 5 and 6 inches below the top of Kennedy's collar [18]. These do not necessarily correspond with bullet wounds, since Kennedy was struck with his arm raised, and multiple photos taken of the President during the motorcade show that his jacket was bunched in the rear below his collar [19]. In addition, on February 19, 2007, the film shot by George Jefferies was released. This 8mm film, taken approximately 90 seconds before the shooting, also clearly shows that President Kennedy's suit coat was bunched up around the neckline around the time of the assassination.

The theory of a "single bullet" places a bullet wound as shown in the autopsy photos and X-rays, at the first thoracic vertebra of the vertebral column. The official autopsy report on the President, Warren Exhibit CE 386 [20] described the back wound as being oval, 6 x 4 mm, and located "above the upper border of the scapula" [shoulder blade] at a location 14 cm (5.5 in) from the tip of the right acromion process, and 14 cm (5.5 in) below the right mastoid process (the boney prominence behind the ear). The report also reported contusion (bruise) of the apex (top tip) of the right lung in the region where it rises above the clavicle, and noted that although the apex of the right lung and the parietal pleural membrane over it had been bruised, they were not penetrated. The report also noted that the thoracic cavity was not penetrated.

The concluding page of the Bethesda autopsy report [21] states: "The other missile [referring to the body-penetrating bullet] entered the right superior posterior thorax above the scapula, and traversed the soft tissues of the supra-scapular and the supra-clavicular portions of the base of the right side of the neck. This missile produced contusions of the right apical parietal pleura and of the apical portion of the right upper lobe of the lung. The missile contused the strap muscles of the right side of the neck, damaged the trachea, and made its exit through the anterior surface of the neck."

Many years after the Warren Commission report, Representative Gerald Ford stated he changed a draft of the Warren Report to indicate the bullet entered the "base of the back of [Kennedy's] neck", rather than "his back at a point slightly above the shoulder" but said he did not do it as part of a conspiracy. The original Bethesda autopsy report, included in the Warren Commission report, did conclude from the data it had, that this bullet passed above the top of the lung outside the thoracic pleura, and therefore through the president's neck. [22]. Ford's description also matched a drawing prepared for the Commission under the direction of Dr. James J. Humes, supervisor of Kennedy's autopsy, who in his testimony to the Commission said three times that the entrance wound was in the "low neck." (The Commission was not shown the autopsy photographs.)

The conclusion of bullet entry specifically at the first thoracic vertebra was made in a 1979 report on the Kennedy assassination by the HSCA Forensic Pathology Panel, which created Figure[24][23] for their report to demonstrate this entrance location. This position is consistent with the back wound location in Figure[4][24]of their report, a drawing made from one of the still-unreleased autopsy photos. It is also consistent with the unofficial versions of this photo available on the internet [25]. The HSCA examined these photographs and X-rays before rendering its opinions as to bullet entry and exit locations, and obtained testimony from autopsy physicians that these were the correct photographs and X-rays taken during the autopsy.

Importance of bullet entry level to theory

The importance of how low or high the bullet struck the President in the back is a matter of possible geometry. The Sibert/O'Neill FBI autopsy report original made by two FBI agents (Special Agents James W. Sibert and Francis X. O'Neill) present at the autopsy preserves genuine confusion amongst medical doctors present during the autopsy, caused by apparent lack of an exit wound, which was cleared up later in the official report after new and more complete information became available (the exit had been hidden by a tracheotomy incision). This report does note that the doctor (Commander Humes) at the time said that he was unable to locate an "outlet" for the wound in Kennedy's shoulder (not his back).

At the time of the autopsy, toward the end of the procedure, initial probing of the shoulder wound suggested the bullet entered the base of Kennedy's neck at a 45 to 60 degree angle. However, this angle is precluded by geometry since the shooter, to obtain such a steep angle, would have to be standing on the back of the limousine. The bullet is believed to have been shot from the sixth floor [~60 feet up] of the Texas Book Depository and traveled horizontally ~200 feet at ~16 degree angle [arctan(60/200)]. The street sloped at 3° 9' away from the Depository, making a total angle of about 19 degrees. However, a bullet entering the President's back at the location shown in the preceding autopsy photograph about 1.5 inches below the collar line, passing over the top of the right lung, and exiting at the throat tracheostomy incision wound in the President, as theorized in the "single bullet theory" of the Warren Report could have caused all of the damage to Kennedy and John Connally.

The weight of bullet CE399 was reported in the Warren Commission Report as 158.6 grains. It was found that the weight of a single, unfired bullet ranged from 159.8 to 161.5 grains with an average weight of 160.844 grains.The lead fragments retrieved from Connally's wounds in the wrist (there were no fragments in the chest) weighed about 2 grains.

The oval entrance wound observed on Connally's back and chest is consistent either with the bullet yawing or tumbling on exiting Kennedy's throat (bullets often lose stability when striking a solid object) and entering Connally at an oblique angle or with Connally being turned at an angle to the bullet's direction when hit. The bullet entered just at the edge of the scapula and followed the fifth rib, shattering the last 10 cm of the rib before exiting on the right side of his chest just below the right nipple. According to the theory, the bullet then went through the Governor's jacket cuff about .5 cm from the end, the shirt's french cuff about 1.5 cm from the end, struck and shattered his radius leaving many dark fibres and small fragments of metal in the wound, and exited on the palm side of his wrist above the cuff. (There was a hole about .5 cm from the end of the jacket sleeve and a hole through the back of the doubled french cuff but no exit hole on the palm side.

According to the theory, the bullet emerged from the palm side of the wrist and entered the left thigh. This bullet is thought to be CE399 which was recovered from Governor Connally's stretcher later at Parkland Hospital. CE399 was ballistically matched to the rifle found in the Texas Schoolbook Depository, to the exclusion of all other rifles.

Theorized path of the bullet CE399

Specter reproducing the assumed alignment of the single bullet theory

The following description assumes that bullet CE399 hit high, at the sixth cervical vertebra rather than the third thoracic vertebra: The 6.5 millimeter, 161 grain, round nose military style full metal jacket bullet, which was manufactured by the "Western Case Cartridge Company" and later stored nearly whole in the U.S. National Archives, was first theorized by the Warren Commission to have:

• after an initial supersonic rifle exit muzzle velocity of 1,850 to 2,000 feet per second (560 to 610 m/s), very slightly ballistically arced while traveling 189 ft (58 m) in a downward net angle of 25 degrees (allowing for the 3 degrees downward of Elm Street) then entered President Kennedy's rear suit coat at about 1,700 feet per second (518 m/s),

• passed through President Kennedy's suit coat back, just to the right of his spine, and 5.375 inches (137 mm) below his collar line,

• impacted, then entered President Kennedy 2 inches [50 mm] to the right of his spine, creating a wound documented size of 4 millimeters by 7 millimeters in the rear of his upper back with a red-brown to black area of skin surrounding the wound, forming what is called an abrasion collar. This abrasion collar was caused by the bullet's scraping the margins of the skin on penetration and is characteristic of a gunshot wound of entrance. This abrasion collar was photographically documented to be larger at the lower margin half of the wound, which is strong evidence that the bullet's long-axis orientation at the instant of penetration was slightly upward in relation to the plane of the skin immediately surrounding the wound; however, the skin of Kennedy's upper back slopes inward, and the Croft photo (shot shortly before Kennedy was hit) shows Kennedy slumped forward, both of which would suggest that a shooting position above Kennedy is possible,

• the bullet's passage near the spine is believed to have damaged the President's first thoracic vertebra.(There is debate whether the bullet itself struck the vertebra and caused this damage, or whether a pressure cavity wave created by the bullet's passage was responsible).

• passed through his neck. Warren Exhibit CE 386 reported contusion (bruise) of the apex (top tip) of the right lung in the region where it rises above the clavicle, and noted that although the apex of the right lung and the parietal pleural membrane over it had been bruised, they were not penetrated. This is consistent with a bullet passing through the neck, immediately over the top tip of the right lung (the pressure wave causing bruising to both pleural membrane and apex of lung), but without penetrating the thoracic cavity, or the lung beneath.

• After passing through the neck, the bullet exited President Kennedy's throat, at the centerline below the President's Adam's apple. Within three hours of the assassination, this neck frontal wound was described in an afternoon press conference by the Parkland trauma room #1 emergency physician, Doctor Malcolm Perry, after he attended to the frontal throat wound, as being an "entrance wound". Doctor Perry stated the neck frontal wound "appeared to be" an entrance wound three times during his press conference. However, medical researchers have found that ER doctors frequently make mistakes with regard to entrance and exit wounds, and both Perry and Dr. Carrico, the other attending ER doctor, later testified at the Warren hearing that with a full jacketed bullet the wound in the front of the throat could have been either an entrance or exit wound. . Within nineteen hours of his press conference statement (but after the autopsy had already been completed), Doctor Perry also described via telephone to Doctor Humes, one of the three U.S. Navy Bethesda Hospital military autopsists, that the neck front wound was originally only "3 to 5 millimeters" in circular width before doctor Perry attended to the front throat wound (Humes documented Perry's "3 to 5 millimeters" wound size by writing it down during the phone conversation),

• passed through both sides of his shirt collar-front in alignment with the collar button buttoned, about 7/8 inch below the center top collar button and collar button hole, in line with the throat wound, and with the threads in both bullet-slits forced outward, showing this to be an exit wound

• nicked President Kennedy's tie-knot on its upper left side. Upon clearing the tie-knot the bullet had slowed to about 1,500 feet per second (457 m/s) and had started to tumble,

• traveled the 25.5 inches (650 mm) between President Kennedy and Governor Connally,

• according to the single bullet theory, this bullet impacted and entered Connally's back just below and behind his right armpit creating an 8 millimeter by 15 millimeter elliptical wound, indicating that bullet was fired from an acute angle to the entrance wound point, or that the bullet was tumbling, having hit something (presumably Kennedy); according to Connally, the impact of the bullet was very forceful. In terms of the physics of this impact, this means that the bullet imparted part of its momemtum to Connally's body and therefore the bullet's momentum changed (in speed or direction or both) upon entering his body;

• completely destroyed 127 millimeters (5 in) of Connally's fifth right rib bone as it smashed through his chest interior at a documented 10-degree anatomically downward angle, (post-operative x-rays document that some of the metal fragments remained in Connally's wrist for life and were buried with him many years later. There were no fragments seen in any chest x-rays)

• exited slightly below his right nipple, creating a 50 millimeter, sucking-air, blowout chest wound,

• passed through Connally's shirt and suit coat front, seen in commission photos five inches (127 mm) to the right of the suit coat right lapel, and even with the lowest point of the right lapel,

• slowed to 900 feet per second (274 m/s) (subsonic), and entered through Connally's right upper (outside) wrist, but missed his suit coat sleeve. It penetrated the doubled French cuff shirt sleeve at the wrist area but did not penetrate the cuff on exit (in 2003 Nellie Connally described in her book “From Love Field” that Connally's right hand, French cuff shirt cuff, solid-gold “Mexican peso” cufflink was struck with a bullet, and the cufflink was completely shot off during the attack. This is not evident from the physical appearance of the shirt which bears no mark, tear or hole at the cufflink area. Connally’s cufflink was apparently never found — thus never entered — into the assassination evidence)

• broke his right radius wrist bone at its widest point, depositing metal fragments, (post-operative x-rays document that some of the metal fragments are still buried with him)

• exited the palm (inner) side of Connally's wrist,

• slowed to 400 feet per second (122 m/s) and entered the front side of his left thigh, creating a documented 10-millimeter nearly round wound,

• buried itself shallowly into Connally's left thigh muscles,

• then, at Parkland Hospital, the bullet fell out, perhaps when Connally was undressed,

• landed on a stretcher next to Connally's,

• was discovered by hospital engineer Darrell C. Tomlinson on one of two stretchers on the ground floor of the hospital. Tomlinson has gone on record independent of the Warren Report, stating that he found the bullet on the stretcher next to the one that transported Connally to an operating room table on the second floor of the hospital.

Regarding the bullet that he remembered impacting his back, Connally stated, "...the most curious discovery of all took place when they rolled me off the stretcher and onto the examining table. A metal object fell to the floor, with a click no louder than a wedding band. The nurse picked it up and slipped it into her pocket. It was the bullet from my body, the one that passed through my back, chest, and wrist, and worked itself loose from my thigh."

The Warren Commission's "single bullet," according to all documentation:

• had no thread striations (fine lines etched onto a copper encased bullet tip and/or bullet side casing by clothing threads when the bullet first penetrates clothing threads),

• was marked with no blood,

• was marked with no human tissue,

• had no pieces of clothing attached,

• had lost only 1.5% of its original average weight,

• had a composition that was consistent with the composition of the metal fragments recovered from Connally (see section on neutron activation analysis).

CE399 butt view

This "single bullet," which was full metal jacketed and specifically designed to pass through the human body, was deformed and not in a pristine state as some detractors claim. Though a side view seems to show no visible damage, a view from the end of the bullet shows a significant flattening which occurred when, according to the theory, the bullet struck Connally's wrist, butt end first. The metallurgical composition of the bullet fragments in the wrist was compared to the composition of the samples taken from the base of CE399.

Several of the same type 6.5 millimeter test bullets were test-fired by the Warren Commission investigators. The test bullet that most matched the slight side flattening and nearly pristine, still rounded impact tip of CE399 was a bullet that had only been fired into a long tube containing a thick layer of cotton. (Later tests show that such bullets survive intact when fired into solid wood and multiple layers of skin and ballistic gel, as well.)

CE399 is stored out of the public's view in the National Archives and Records Administration, though numerous pictures of the bullet are available on the NARA website.

Ballistics experts have performed test shots through animal flesh and bones with cloth covering. Under the assumption of an adjusted relative position of President Kennedy and Governor Connally within the car, some, but not all, of the Warren Commission ballistics experts considered it possible that the same bullet that passed through the President's neck may have caused all of the governor's wounds. The Warren Commission as a whole wrote that it was persuaded that the President's neck wound and all of the governor's wounds were caused by a single bullet, although three of the seven members, Sen. Richard Russell, Rep. Hale Boggs, and Sen. John Cooper, have stated that they did not support the theory because it did not fit the evidence.

Discovery Channel's reenactment of bullet CE399's path

JFK — Beyond the Magic Bullet

Airing on November 14, 2004, the Discovery Channel special "Unsolved History: JFK — Beyond the Magic Bullet", attempted to replicate, as well as possible, the conditions of that day. The participants set up blocks of ballistics gel with a substance similar to human bone inside. These studies showed that largely undeformed bullets were possible to produce, if they were slowed by a passage though a tissue-like substance before striking bone. Next, two mannequin figures made of ballistic anatomical substances (animal skin, gelatin, and interior bone-like cast) were set up in the exact relative position of JFK and Connally. A marksman, from a distance equal to that of the sixth floor of the Book Depository building, fired the same rifle model found in the Book Depository, using a round from the same batch of "Western Case Cartridge Company" 6.5x52 mm ammunition purchased with the surplus Carcano weapon in early 1963. The path of their single bullet (followed by high speed photography) duplicated, almost exactly, the wounds suffered by the victims that day, the only difference being that the bullet did not quite have enough energy to penetrate the "thigh" substance in front of the Connally figure, because it struck an extra bone in the "rib" model (i.e., it fractured 2 ribs in the model vs. one rib in Connally). It was also slightly more deformed than CE 399, possibly for the same reason. However, this bullet came close enough to duplicating all wounds in both men with a single shot, with a bullet having little deformation. Thus the theory was proven to be much more plausible than previously thought.[26]

ABC's The Kennedy Assassination: Beyond Conspiracy

In 1993 a computer animator named Dale Myers embarked on a 10-year project to completely render the events of November 22 in 3D computer animation. His results were shown as part of ABC's documentary The Kennedy Assassination: Beyond Conspiracy in 2003, and won an Emmy award.

To render his animation, Myers took photographs, home footage, blueprints and plans, and used them to create arguably the most accurate computer re-creation of events to that time. His work was assessed by Z-Axis who have been involved in producing computer generated animations of events, processes and concepts for major litigations in the United States and Europe.

Their assessment concluded that Myers' animation allowed the assassination sequence to be viewed "from any point of view with absolute geometric integrity" and that they "believe that the thoroughness and detail incorporated into his work is well beyond that required to present a fair and accurate depiction." [27]

Myers' animation found that the bullet wounds were consistent with JFK's and Governor Connally's positions at the time of shooting, and that by following the bullet's trajectory backwards could be found to have originated from a narrow cone including only a few windows of the sixth floor of the School Book Depository, one of which was the sniper's nest of boxes from which the rifle barrel had been seen protruding by witnesses.

In the same ABC documentary, Myers uses a close-up examination of the Zapruder film to justify the "single bullet theory." He points out a little-known anomaly on the Zapruder film. When Kennedy's limousine appears from behind the street sign in Dealey Plaza, there is a moment — seen between frames 223 and 224 on the Zapruder film — where the right side lapel of Governor Connally's jacket appears to "pop out," as if being pushed from within by an unseen force. Myers theorizes that this is the moment of impact, when both Kennedy and Connally were struck by the same bullet from Oswald's rifle. Myers also points out that — in frames 225-230 of the Zapruder film, as Kennedy appears from behind the street sign — both Kennedy and Connally are simultaneously reacting in pain to the impact of the bullet.

Neutron activation analysis of bullet fragments

Warren Commission documents released after the publication of its report revealed that the FBI had arranged for bullet CE399 and the various fragments found in the car and in Governor Connally’s wounds to be examined using a method known as neutron activation analysis (NAA). NAA is a very accurate, non-destructive method of determining the relative concentrations of trace elements in a sample of matter. The data from the tests performed for the FBI were inconclusive as to the origins of the fragments.

In 1978 the HSCA asked physicist Dr. Vincent P. Guinn to review the NAA data and conduct new tests. Dr. Guinn did so and presented his results and analysis to the Committee. Dr. Guinn stated that initially he agreed with the earlier conclusion. However, after examining the old and new NAA data further, he concluded that all the fragments probably came from two bullets, one of which was the whole bullet, CE399.[28]

WC Exhibit	Silver (ppm)	Antimony (ppm)
399 Whole bullet (labeled Q1)	7.9 ± 1.4	833 ± 9
567 Limousine fragment (labeled Q2)	8.1 ± 0.6	602 ± 4
843 Fragments from head wound (labeled Q4 and Q5)	7.9 ± 0.3	621 ± 4
842 Wrist fragment (labeled Q9)	9.8 ± 0.5	797 ± 7
840 Limousine fragment (labeled Q14)	8.6 ± 0.3	638 ± 4
- second (labeled Q14)	7.9 ± 0.5	647 ± 4
573 fragment from bullet fired at Gen. Walker 's residence	20.6 ± 0.6	17 ± 2
141 unfired bullet recovered from Oswald's rifle	-	15 ± 1
- second	22.4 ±1.0	-

The NAA data obtained from the various bullet samples (1 HSCA 538[29] and 1 HSCA 550[30])

Dr. Guinn compared antimony concentrations of Exhibits CE840, 843 and 567 with that of Exhibits CE399 and 842. He reasoned:

Accordingly, neutron activation analysis of the evidence specimens tested indicates the presence of only two bullets in Group I. It is highly probable that the specimen tested from Ql (the stretcher bullet) and the specimen tested from Q9 (the fragments from Governor Connally's wrist) are from the same bullet. It is highly probable that Q2 (large fragment found in the limousine), Q4 and 5 (fragments from President Kennedy's brain) and Q14 (smaller fragments found in limousine) are all from a second bullet. There is no evidence of a third bullet from any of the evidence specimens tested.[31]

Dr. Guinn had some difficulty in stating the precision that he could give to this probability:

Dr. GUINN. I wish that I could put a number on it, as we often can do, that is, calculate a probability, but we really don’t have the background information to make a numerical calculation in this case. One can only show what information we do have, and that is that you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets, but you do find wide composition differences from bullet to bullet for this kind of bullet lead. Thus, when you find two specimens that agree this closely, you can say it looks indeed like they are pieces from the same bullet.

Mr. WOLF. Would you state that your conclusion is more probable than not, highly probable, or what is the degree of certainty of your conclusion?

Dr. GUINN. I would say highly probable, yes. I would not want to say how high, whether it was 99 percent or 90 percent or 99 .9 percent. I can’t make a calculation like that.[32]

The underlying assumption in Dr. Guinn’s analysis was that silver and antimony concentrations in the bullet lead varied significantly between bullets but not within individual bullets. Significant differences in concentrations between samples, therefore, would mean that the samples originated with different bullets. Dr. Guinn’s assumption was based on sample data that he had obtained by analysing concentrations of antimony, silver and other trace elements in Mannlicher-Carcano ammunition from Western Cartridge Co., which was the ammunition found with Oswald’s rifle. He observed that while there was some variation of concentrations within individual bullets, he found that the variation between bullets is wider.

There seems to be relatively greater heterogeneity between bullets from Dr. Guinn’s data, although it may be noted that the concentrations of antimony, for example, varied substantially within a sample bullet[33]. This lack of perfect homogeneity within individual bullets was acknowledged by Dr. Guinn:

The results are shown in Table II-C[34] . As can be seen, of the three bullets sampled, one (6001 C) is fairly homogeneous in all three elements ; one (6002 A) is fairly homogeneous in Ag and Cu, but not so homogeneous in Sb ; and one (6003 A) is fairly homogeneous in Cu, but not homogeneous in Sb or Ag . However, comparison of Table II-C with Table II-A[35] indicates that, in general, the heterogeneity within an individual Mannlicher-Carcano bullet is much less than the heterogeneity from one bullet to another. One of the primary conclusions, therefore, of the results of the UCI background study of MC bullet lead indicates a wide range of Sb values, from bullet to bullet, but reasonable homogeneity within an individual bullet.[36]

Guinn, however, acknowledged that the assumption of heterogeneity between bullets was not necessarily true for all bullets:

However, the earlier data and these more recent data do show some Mannlicher-Carcano bullets that cannot be distinguished from one another via only their antimony and silver concentrations. From these data, it appears that if 2 cartridges are removed at random from a box of Mannlicher-Carcano cartridges, although it is highly probable that they would differ significantly in their antimony and silver concentrations, it is at least possible that they might not. (1 HSCA 534 - footnote)[37]

Dr. Guinn's observation appears to be borne out by the profiles of CE141 and CE573 which have very similar silver and antimony concentrations but are from two different bullets.

Dr. Guinn’s data and analysis was thought to provide important support for the Single Bullet Theory. If there had been greater differences in concentrations of trace elements between fragments, the theory could not stand.

Can NAA be used to prove the SBT?

Whether the NAA data can be used to actually exclude the possibility that there were fragments from more than two bullets in the wounds and the car has been the subject of controversy.

Professor Ken Rahn of the University of Rhode Island [38], a chemist and meteorologist who has a long standing interest in the Kennedy Assassination, maintains that the NAA data excludes a “three bullet hit” and proves the SBT actually occurred. Professor Rahn’s analysis can be found on his “Academic JFK Assassination Site”[39]. The analysis was published in 2004 (Rahn K.A., Sturdivan L.M., "Neutron Activation and the JFK Assassination. Part I. Data and Interpretation." Journal of Radioanalytical and Nuclear Chemistry. 262(1):205-213 [40] and Part II. Extended Benefits 262(1): 215-222[41]co-authored with Larry Sturdivan, a Warren Commission and HSCA ballistics expert. Essentially Rahn/Sturdivan say that the possibility that the wrist fragment CE842 (with an antimony concentration of 797 ± 7 ppm) did not come from the base of the whole bullet CE399 (the sample from which had an antimony concentration of 833 ± 9 ppm) is so statistically improbable as to be excluded as a reasonable possibility.

However, in an article published in July 2006 in the Journal of Forensic Science by Dr. Erik Randich and Dr. Patrick M Grant ("Proper Assessment of the JFK Assassination Bullet Lead Evidence from Metallurgical and Statistical Perspectives", J. Forensic Sci. Vol. 51, p. 722[42]), the authors took a much different view of the NAA data and the metallurgical profile of the Mannlicher-Carcano ammunition. Dr. Randich is a metallurgist with the Lawrence Livermore National Laboratory. Dr. Grant, a chemist, is the director of the Lawrence Livermore Forensic Science Center and is a former colleague of Dr. Guinn's at the University of California, Irvine. The authors conclude:

Thus, elevated concentrations of antimony and copper at crystallographic grain boundaries, the widely varying sizes of grains in MC bullet lead, and the 5-60 mg bullet samples analyzed for assassination intelligence effectively resulted in operational sampling error for the analyses. This deficiency was not considered in the original data interpretation and resulted in an invalid conclusion in favor of the single-bullet theory of the assassination. Alternate statistical calculations, based on the historic analytical data, incorporating weighted averaging and propagation of experimental uncertainties also considerably weaken support for the single-bullet theory. In effect, this assessment of the material composition of the lead specimens from the assassination concludes that the extant evidence is consistent with any number between two and five rounds fired in Dealey Plaza during the shooting.

...

The end-result of these metallurgical considerations is that, from the antimony concentrations measured by VPG [Dr. Vincent P. Guinn] in the specimens from the JFK assassination, there is no justification for concluding that two, and only two, bullets were represented by the evidence. Nor is there justification for concluding that three, four or five bullets were more or less likely than two bullets.

Sturdivan wrote a response to the Randich/Grant paper dated 14 August 2006:

This is similar to watching a videotape of a bank robber and discovering that the two bank robbers were identical twins. Randich and Grant would solemnly declare that since you could not tell the bank robbers apart, it could have been any two people that robbed the bank. Obviously, it isn't how close the two groups of recovered bullet evidence are to each other that matters, it's the chance that the lead from a third source could match as well as the other members of the group do. For this comparison, one must characterize the range of antimony content in the population of bullets available to a potential shooter in the early 1960s, a point that Randich and Grant choose to ignore.

...

Obtaining exact concentration of trace metals in soft lead cores was beyond the abilities of even the FBI in 1963, so the best a conspirator could do to match CE 399 or CE 567 was to use another bullet from the same lot. [Most other bullets available in 1963 would have had either trace antimony or "antimony content... orders of magnitude larger than that in the recovered bullet evidence"] Vincent Guinn measured the antimony content in that lot of WCC/MC bullets and found that it ranged from near zero to a few thousand ppm. This prompted him to state that the recovered samples were all in the high range of antimony concentration, not only from that lot, but for any of the four lots of these bullets. Ken Rahn and I properly characterized the distribution of antimony in that lot and found that it did not differ significantly from the other three lots, and used that distribution to show that a randomly selected WCC/MC bullet would have only a low probability of matching either group so closely as other members of that group did. This is true even if that hypothetical "other gunman" selected other bullets from the same box from which CE 399 and CE 567 were drawn. Furthermore, using measurement errors not artificially inflated by the irrelevant factors used by Randich and Grant shows that the obvious grouping is (not surprisingly) the correct one. Earlier NAA tests conducted by the FBI, though not disclosed to the Warren Commission, showed results virtually identical to Guinn's. These tests were run with different samples cut from CE 399 and CE 567, independently verifying that the two groups could be distinguished from each other. Note that this result is not necessary for calculation of the probability that a random bullet would match the antimony content of the fragments recovered from either of the two men as well as the recovered bullet or major bullet fragment (within the same group) does.

The conclusion of Randich and Grant had been advanced earlier by Dr. Arthur Snyder of the Stanford Linear Accelerator Laboratory, whose 2001 paper is also found on Prof. Rahn's site[43].Dr. Snyder found that Guinn's sample data was insufficient to base any conclusion about the probability that the fragments were made by only two bullets. He offered a suggestion for clearing the controversy (at p.16):

"The situation could be cleaned up with more measurements to establish the properties of WCC bullets. More and more accurate measurements of repeated samples from the same bullet would allow one to characterize the single bullet PDF’s (probability density function) more accurately. Detailed repeated measurement of CE399 would be especially useful in this regard. More measurements of a larger number of bullets would allow one to get a more accurate estimate of the antimony distribution giving us a better estimate of the two bullet likelihood."

Forensic Use of Compositional Bullet Lead Analysis

The technique used by Guinn to analyse the bullet lead from the JFK assassination was a form of what has become known as Compositional Bullet Lead Analysis (CBLA). Instead of using only one element (antimony) to identify a bullet, as Guinn used, the FBI developed a CBLA procedure in which the concentrations of six different elements were measured. The theory was that each lot of bullet lead has a unique profile of these six elements. However, in a 2002 paper ("A Metallurgical Review of the Interpretation of Compositional Bullet Lead Analysis", (2002) 127 Forensic Science International, 174-191[44]) co-authored by Randich and by former FBI Chief Metallurgist, William Tobin, the authors analysed several years of data kept by two lead smelters that supply the raw material for ammunition. According to the authors, manufacturers measure and record the levels of at least 15 trace metals, including antimony, from samples taken when smelters start and finish pouring a batch of lead into casts. Randich, Tobin et al examined records for 1998 to 2000 held by the Sanders Lead Company in Alabama and Gopher Resources Corporation in Minnesota. They found many instances where it was impossible, using the FBI's chemical profile standards, to distinguish between batches poured months apart.

The 2002 Tobin/Randich paper prompted the National Academy of Sciences (Board on Chemical Science and Technology) to review the science of bullet lead analysis. In a report in 2004[45] the NAS found the scientific basis for matching bullet sources from the analysis of bullet lead composition as practiced by the FBI was flawed. As a result of that report, the courts appear to have stopped accepting this evidence[46] and the FBI has stopped using bullet lead analysis for forensic purposes[47].

The NAS report on CBLA, and its relevance to the Dr. Guinn's analysis of bullet lead in the JFK assassination, is the subject of comment by Randich and Grant in their 2006 paper at page 719 [48].

Criticisms

Critics claim that a bullet that passed through several layers of clothing and flesh, destroyed a five inch (127 mm) section of a rib, broke a wrist radius bone, and shed metal fragments (some of which are buried with Connally) could not be in such nearly pristine shape, especially given that the, supposedly, same type "headshot" bullet, according to the Warren Commission, completely broke apart after passing through only two layers of less-dense skull bone.

Proponents point out that these questions have been answered by later study (see Unsolved History above): 160 gr. bullets of this type only fragment if they hit bone at high velocity; the CE 399 bullet is postulated to have been slowed considerably by passage though JFK's neck with little or no bone contact, then to have hit rib bone side-on, after tumbling through more chest tissue. Such tests in skin, gelatin, and bone-mock-up models have produced bullets with little deformation.

Analysis of the Zapruder film

Critics of the single bullet thesis question not only the bullet's trajectory and relative lack of damage, but also the question of timing of hits to both the president and Connally. A single bullet would have passed through both men in less than 1/100th of a second, which means that a strike of both men by a single bullet would have happened too quickly to be caught on more than a single Zapruder frame (these were exposed at 1/18th second intervals). From the Zapruder film one can see Kennedy with his hands in front of his chest near his throat as he emerges from behind the sign at Zapruder frame 225.

According one popular version of the single bullet theory (promoted by Gerald Posner in his book, Case Closed), the interval between frame 223 and 224 is the time the same projectile passes through both JFK and Connally's body. It is not obvious at this point (frame 224), whether Connally has, or has not, been hit; however Connally, but not other limosine occupants, is newly-blurred in frame 224 but not in frame 223. Connally himself, in analyzing the frame-by-frame Zapruder film, identified his own hit later, at about Zapruder frame 230, whereas JFK is certainly hit about Zapruder frame 224, a third of a second earlier. Beginning immediately after frame 224, Connally rapidly raises and then lowers both arms, then turns to see what has happened to Kennedy.

He must have been hit before this point, if hit by the same bullet, since the President is already reacting. Connally's cheeks then puff out, and his mouth opens. Many suggest that he is beginning to show the shock of the bullet. Others suggest that Connally is doing exactly what he said he did in reaction to hearing the first bullet: he said he realized an assassination was unfolding so he turned to see the President (WC 4 H 132-133:[49]). It is at this point that some critics of the single bullet theory believe Connally is actually hit by a second and separate bullet, and this is also what Connally himself believed (some other critics believe he was hit later). Proponents of the single bullet thesis argue that Connally is simply exhibiting a delayed pain reaction to being been hit by the same bullet that hit Kennedy, a third of a second earlier.

Some critics believe the puffing out of Connally's cheeks is simply physics at work, as the bullet collapses one of his lungs, forcing air into his mouth. Other critics believe that the puffing of Connally's cheeks result from him shouting "oh, no, no, no" which his wife, Nellie, said he shouted after the first shot but before the second shot. (WC 4 H 147: [50]. Connally said that he felt no pain from his wounds until he arrived at Parkland Hospital. Since a collapsed lung is characterised by sharp chest pain and very painful breathing, the absence of pain reported by Connally may be considered when assessing whether the cause of Connally's puffed cheeks, seen from Zapruder frame 240-250, is the result of a collapsed lung.

When an enhanced copy of the Zapruder film was released in 1998, many felt the delayed reaction theory was debunked. Others, particularly Posner, noted that Connally's right lapel flips up at frame 224 (it hides the right part of his white collar in frame 224, which is far more clearly seen in both frames 223 and 225). In this same frame, as noted above, Connally suddenly becomes blurred with regard to the rest of the automobile (Connally is clear in frame 223). Frame 224 is precisely the best-posited frame of the impact of the bullet to Kennedy, who is still behind the sign at this point. Zapruder himself does not appear to jump until frame 227, blurring all contents of the automobile.

Connally's immediate reaction after frame 224, including a flinch in which he flexes both elbows and brings his hat up, is seen by some as an unconscious reaction to the strike (single frames of this reaction appear to show Connally unharmed, with hat held up in front of his chest, while Kennedy behind him has already clearly been hit). Others see this as the Governor's reaction to the sound of the first shot. Immediately after the arm spasm, Connally begins a motion which drops his right shoulder and holds his right arm pinned to his right side, including a slow rolling motion toward this side. He also is seen to look over his right shoulder at Kennedy and shows an expression of pain only after turning his head back toward Zapruder's position around frame 275. Some believe that Connally was hit in the chest just before frame 275.

In the Oliver Stone movie JFK, Stone goes to great lengths to debunk the single bullet theory, although some minor discepancies exist between the narrative and the historical record. One example is when he shows both Kennedy and Connally seated directly in front of each other at the same height. In fact, Connally was seated in a jump seat the edge of which was 3 inches inboard and possibly 4 inches lower than Kennedy.

The House Select Committee concluded that the Governor could have been as much as 6 inches (15 cm) to the left of the President. Moreover, Stone has Connally looking straight ahead. However, when Connally emerges from behind the freeway sign at Zapruder frames 222-223, he is clearly rotated significantly to his right. These points are of critical importance in assessing whether the bullet that passed through Kennedy could have caused Connally's injuries. Computer recreations showing accurate body positioning of the two men show that their injuries, if caused at Zapruder frame 224, fall on a line which emanates from a circle enclosing several windows on the sixth floor of the Texas Book Depository, and includes the window of the sniper's nest.

Connally continued to hold his hat after the single bullet struck and broke his right wrist. Critics contend this is not physically possible, However, in the Zapruder film Connally continues to clutch the hat even after Kennedy's head wound, this being a point after which everyone (including critics) agree Connally must have already been hit. In fact, Connally's wife, Nellie Connally, stated that he held on to his hat until he was put on a stretcher at Parkland Hospital. Thus, it is clear that Connally continued to hold the hat after being hit. Wrist fracture would not preclude ability to hold a light object such as a hat, and Connally's nerve damage was limited to a superficial branch of the radial nerve which served a sensory function only, and would not have interfered with his grip strength (nor was Connally's hand function in any way permanently harmed).

Another criticism that has been made of the single bullet theory is that it requires a missed shot. The Warren Commission Report contained a subchapter entitled "The Shot that Missed"[51]. If two bullets account for all the wounds and there was no shot that struck just the car, then obviously one must have missed entirely. This gave the Commission great difficulty. "The Shot that Missed" addresses each of the three shots and provides the arguments for and against such a shot missing, but reaches no firm conclusion as to which shot missed (WC Report 117[52].

The Warren Commission concluded, based on the "preonderance of evidence," that one shot probably missed the Presidential limousine and its occupants, but that "the evidence is inconclusive as to whether it was the first, second, or third shot which missed." Three FBI shooters using Oswald’s rifle fired seven sets of three shots as quickly as possible while aiming at three targets spaced at distances comparable to those from the sixth floor Texas School Book Depository window to the President’s limousine. All 21 shots hit within nine inches of the centre of the respective targets. (See the evidence of Ronald Simmons, WC 3 H 447-448[53])

There is eye-witness testimony that all three shots struck the occupants of the vehicle: 1. many witnesses to the assassination (for example, T.E. Moore[54], Nellie Connally[55], David Powers[56], Gayle Newman[57] and William Newman[58], John Chism [59] and Faye Chism[60], James Altgens[61], Abraham Zapruder[62], S.A. Clint Hill[63], Linda Willis[64], S.A. Roy Kellerman[65], S.A. George Hickey[66], S.A. Sam Kinney[67], S.A. Paul Landis[68],Harold Norman[69]) stated that the President reacted to the first shot (most saying he reacted by slumping forward, to the left or both, or moving his hands to his neck area). Only Dallas reporter Mary Woodward thought there may have been no reaction to the first shot. She reported the following day (Dallas Morning News, November 23, 1963 "Witness from the News Describes the Assassination"[70]) that she thought that no one was hit by the first shot and that the President did not react until after the second shot or third shot, both of which were very close together. Her statement a few weeks later to the Warren Commission[71], however, indicates that the reaction she may have been referring to was the slump after the head shot. 2. Governor Connally[72] and his wife, Nellie Connally[73] were adamant that the second shot struck the Governor in his back — he distinctly recalled the forceful impact and that this was after he heard the first shot, realized it was a rifle shot and turned to his right to look for the President (though he also testified he did not actually make it far enough to see the condition of the President, and he began to turn back when he was shot). 3. One shot (obviously a later one) struck the President in the head.

A further criticism of the single bullet theory has to do with the apparent trajectory from the sixth floor window of the Texas School Book Depository through the President being to the left of the midline of the Governor when it crossed the plane of the back of Governor Connally's seat. The Governor was struck on the right armpit. In the photographs it appears that Governor Connally is seated in the middle of the jump seat and the President is to the right side of his seat with his right arm resting on the top of the limousine side. According to the analysis done by the HSCA, the angle from the 6th floor window of the Texas School Book Depository to the limousine at frame 190 or so was about 13 degrees[74].

If Governor Connally was seated in the middle of his seat, the bullet should have struck the Governor to the left of his spine. The only wound on the Governor's left side was in his thigh. Neither the Warren Commission nor House Select Committee on Assassinations considered the possibility that the bullet that passed through the President wounded the Governor only in the thigh. The path to the thigh appears to fit a straight line path through the President's neck with the Governor's shoulders turned to the right. The HSCA concluded that the thigh wound was made by a bullet travelling at a much slower speed than one would expect the bullet to have after exiting the President's neck (though the single bullet theory holds that the bullet which struck Connnally's thigh had also passed through his wrist, slowing it down in the process). Governor Connally said that he never felt this thigh wound at any time until the next day. On the other hand, Dr. Shires, who operated on Governor Connally's thigh wound, thought that the wound to the thigh (which he said extended to the region of the femur) could have been made by a bullet travelling at high speed striking the thigh on an angle.[75]

The HSCA concluded, however, that Governor Connally was not seated in the middle of his seat but was about 7-8 inches to the left of that position[76]. NASA Engineer Thomas Canning provided an analysis of the photograph taken by Hugh Betzner from the rear of the limousine a moment prior to the first shot (according to Betzner, he took the picture and began winding his camera to take another when the first shot sounded: WC 19 H 467[77]). It has been determined that Betzner's photograph was simultaneous with Zapruder frame 186[78]. Mr. Canning could not see the Governor's shoulder in Betzner's photograph and concluded that this meant that the shoulder was obscured by the person standing in front of Betzner. This, he said, put the shoulder well to the left of the president's midline putting his right armpit in line with a right-to-left path through the President's neck. The analysis and conclusion of Canning depends on the correctness of the assumption that Governor Connally's shoulder would have been visible if the man in front of Betzner was not there. The photo taken by James Altgens taken from a similar angle earlier on Houston Street would seem to indicate that Governor Connally's shoulder was below the line of sight[79].

The Single Bullet Theory as proposed by the House Select Committee on Assassinations and later by author Gerald Posner in his book Case Closed (which is that the first shot missed and the second shot passed through both the President and the Governor) has also been criticised on the grounds that it does not fit the shot pattern recalled by most of the witnesses (which was: first shot, a longish pause and then two shots in rapid succession, the second shot being after the midpoint between the first and last shots). The Warren Commission remarked on the "substantial majority" of witnesses who recalled that the shots were not evenly spaced [80] but did not attribute much significance to the shot pattern. If the first shot occurred after frame 150 of the Zapruder film, the second shot could not have occurred before frame 240 in order to have a shot pattern in which the last two shots were noticeably closer together (the head shot obviously occurred between frames 312 and 313).

If the last two shots were closer together, Governor Connally was either wounded in the back on the first shot or he was not wounded until many frames after frame 240. This "late hit" view was abandoned in April 1964 because the FBI expert Robert Frazier expressed the opinion (as did Governor and Mrs. Connally) that the Governor must have been hit in the chest by frame 240.

External links

• Zapruder film footage, including individual frames referenced in this article -- This is the "Costalla combined edit", hosted at a site which argues that the film itself is a forgery
• Kennedy Assassination Home Page: The Single Bullet Theory
• photos, pictures and diagrams critical of the single bullet theory
• Computer reconstruction supporting the single bullet theory
• The Warren Commission "single bullet theory"
• Single Bullet Theory
• Magic Bullet Theory - Dr James H. Fetzer
• New Documented Information on CE399 and its Provenance (April, 2005)
• Sibert/O'Neill FBI autopsy report original. And [81] cache. This primary document preserves the notes of two FBI agents (Special Agents James W. Sibert and Francis X. O'Neill) who were present at the autopsy and took notes. The early report preserves genuine medical doctor confusion present during the autopsy, caused by apparent lack of an exit wound for the CE399 entry, which was cleared up later in the official report after new information became available. However, as a primary piece of observation by medical laymen, the report is useful.
• Bullet Evidence Challenges Findings In JFK Assassination, May 17, 2007 - sciencedaily.com