Proper assessment of the JFK assassination bullet lead evidence from metallurgical and statistical perspectives

The bullet evidence in the JFK assassination investigation was reexamined from metallurgical and statistical standpoints. The questioned specimens are comprised of soft lead, possibly from full-metal-jacketed Mannlicher-Carcano (MC), 6.5-mm ammunition. During lead refining, contaminant elements are removed to specified levels for a desired alloy or composition. Microsegregation of trace and minor elements during lead casting and processing can account for the experimental variabilities measured in various evidentiary and comparison samples by laboratory analysts. 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.     

Bullet Caliber and Type Categorization from Gunshot Wounds in Sus Scrofa (Linnaeus) Long Bone

Studies on ballistic trauma to the ribs and thorax, cranium, and long bones demonstrate the potential of obtaining a bullet caliber from an entrance wound. In order to validate prior research on caliber estimation in bone tissue and assess the viability of bullet type determination based on the macroscopic evidence at the entrance wound, thirty fleshed pork (Sus scrofa) shoulders (humeri) were shot with either lead or copper jacketed bullets in one of three calibers; 0.22, 9 mm, or 0.38. Overall, our findings are consistent with previous research indicating that calibers can be grouped into “small” and “large” categories. Bullet type, lead or copper jacket, can be ascertained based on cortical flaking and the analysis of materials deposited around the entry wound. The addition of this evidence holds value in cases where no firearm or ballistic evidence is recovered from a crime scene.     

Influence of Muzzle Instability on Bullet Deflection after Perforating Laminated Particleboards

The influence of muzzle instability on bullet deflection, when perforating laminated particleboards, was studied with three different handgun bullet types. The mean deflection angles of .32 Auto FMJ and .38 Special SJHP bullets were calculated to be 0.90° and 0.83°, respectively after perforating particleboards orthogonally at a 1 m muzzle-to-target distance. The mean angles dropped to 0.70° and 0.58° at a 15 m muzzle-to-target distance. The differences in deflection angles proved to be statistically significant (p < 0.05) with p-values of 0.023 and 0.001, respectively. The mean calculated deflection angles of .38 Special LRN bullets also dropped from 1.51° to 1.38° when the muzzle-to-target distance was increased from 1 to 15 m, but this difference was not significant (p-value of 0.357). The results support the hypothesis that muzzle instability has an influence on deflection. The possible implications for shooting incident reconstructions and for future research are discussed.     

The Critical Angle for Perforation versus Ricochet of a .38 CAL. LRN Bullet on a Windshield

From forensic point of view, it is important to clarify the condition whether ricochet or perforate for a bullet fired toward the automobile windshield. The purpose of this study was to specify the critical angle at which the ricochet of the fired bullet takes place. To estimate the result of firing, a rigid‐body dynamics simulation of the bullet together with the test‐firing using .38 CAL. LRN bullet was examined. It was found both from numerical simulation and firing test that when the incidence angle is <45°, a complete perforation of the windshield was observed, whereas the bullet ricocheted remaining a characteristic damage on the windshield when the incidence angle is >60°. To measure the static failure resistance of various windshields, static indentation test was also examined.     

Upon a failure to equal entry and exit wounds: a possible case of tandem bullets in view of the literature

Forensic medicine specialists take account of the projectiles remaining in the body when determining whether there are an equal number of entry and exit wounds. The absence of projectiles should suggest blank cartridges, a single exit wound despite several firings and bullet embolization, whereas the presence of more projectiles than expected may indicate tandem projectiles and multiple projectiles entering through the same hole. Radiological examination of the whole body, follow-up of the bullet trajectories, examination of the clothes, and examination of the gun and projectiles play a key role in solving difficult cases. We review such situations based on a case of tandem bullets. Two 7.65-mm bullets created lethal wounds entering through a 32-year-old victim's neck followed the same trajectory to a certain point and diverted. We discussed the possibilities in cases that show inequalities between entry and exit wounds, in light of relevant literature.     

The Accuracy and Repeatability of Reconstructing Single Bullet Impacts Using the 2D Ellipse Method

When a bullet punctures a surface, it leaves behind a bullet impact, which can be analyzed in order to determine the origin and trajectory path from which a bullet was discharged using many different scientific methods to reconstruct a shooting scene. The purpose of the research was to test the accuracy and repeatability of reconstructing the impact angle of single bullet impacts using the ellipse method. The research was conducted by firing various calibers of ammunition into drywall panels positioned at varying angles of incidence from 88° until ricochet occurred. This was done in order to determine which caliber type and angle of incidence are most accurate and precise for reconstructing a shooting scene. The study examined four caliber types fired into drywall panels, with 5 repeated shots for each of the 11 angles of incidence (n = 220). Furthermore, 31 participants partook in the study to estimate a bullet impact angle of incidence utilizing the ellipse method. The results show that the best performance (accuracy and repeatability) is seen with the measurements of the 0.45 caliber ammunition. When angle of incidences is low (<64°), the performance (accuracy and repeatability) was seen to be better in all caliber ammunitions. Overall, the data provided for single bullet impacts deposited in drywall show that the ellipse method is useful in providing measurements for most crime scene reconstruction purposes and has also demonstrated that results vary depending on the type of ammunition, firearm, and angle of incidence being examined.     

Discordance of Gross and Histologic Findings in Estimating the Range of Fire of Gunshot Wounds

Forensic pathologist use soot and/or stippling surrounding entrance gunshot wounds in categorizing range of fire. If absent, some pathologists suggest utilizing histology when the range is diagnostically critical. This study investigates the concordance of macroscopic and microscopic findings in estimating range of fire by evaluating gunshot entrance and exit wounds made through human tissue analogs at defined distances using two handgun calibers. Examination of over 150 entrance wounds verified the ease of visually detecting soot from a muzzle distance of contact to 1 foot (30.5 cm), and its absence at 9 feet (274.3 cm). Distinctly apparent was bullet wipe surrounding the entrance wounds regardless of muzzle distance. Although variations existed, dark material was histologically identified in many skin, soft tissue, and bone sections at all ranges with both calibers. These nonparallel results decrease the dependability of histology for range of fire estimation and reinforce using gross observation.     

The application of geographic information systems and spatial analysis to assess dumped and subsequently scattered human remains

This study utilizes geographic information systems (GIS) and spatial analysis (SA) technology to address the problems associated with prediction of location and effective recovery of dumped and scattered human remains in Louisiana. The goals are to determine if a selective bias exists in Louisiana as to where and when human remains are dumped and to assess whether or not geographically specific patterns exist in the dispersal of human remains. We hypothesized that a positive relationship exists between postmortem interval (PMI) and dispersal distance, and that there are negative relationships between PMI and dispersal direction and between dispersal direction and distance. Our results indicate that, in Louisiana, remains are more often dumped in rural areas away from a structure, and are found within (1/4) mile of the nearest road. For Louisiana, no seasonal bias was found in the analysis of when remains are dumped. Furthermore, with the exception of the relationship between PMI and the shortest distance remains were dispersed, no geographically specific patterns were detected in the analyses of dispersal distance, dispersal direction, and PMI.     

The Use of Near‐Infrared Photography to Image Fired Bullets and Cartridge Cases

An imaging technique that is capable of reducing glare, reflection, and shadows can greatly assist the process of toolmarks comparison. In this work, a camera with near‐infrared (near‐IR) photographic capabilities was fitted with an IR filter, mounted to a stereomicroscope, and used to capture images of toolmarks on fired bullets and cartridge cases. Fluorescent, white light‐emitting diode (LED), and halogen light sources were compared for use with the camera. Test‐fired bullets and cartridge cases from different makes and models of firearms were photographed under either near‐IR or visible light. With visual comparisons, near‐IR images and visible light images were comparable. The use of near‐IR photography did not reveal more details and could not effectively eliminate reflections and glare associated with visible light photography. Near‐IR photography showed little advantages in manual examination of fired evidence when it was compared with visible light (regular) photography.     

9mm警用转轮手枪橡胶弹射入口的形态特征

目的观察橡胶弹射人口的形态特征,并探讨其法医学意义。方法使用9mm警用转轮手枪发射橡胶弹,在实验动物胸腹部侧面垂直射击,射击距离分别为紧密接触射击（0cm）,相对接触射击（1～6cm）,近距离射击（6-60cm）和远距离射击（60cm～有效射程25m）。92式手枪采取相同方式射击实验动物作为对照。观察射入口的形态特征,制作组织病理学切片,HE染色显微镜下观察。结果橡胶弹接触射击和近距离射击,射入口边缘整齐,有明显的擦拭轮、挫伤轮和火药斑纹;远距离射击,可见射人口边缘撕裂,挫伤轮明显增宽,皮下出血显著;与手枪弹射入口形态特征明显不同。结论9mm警用转轮手枪橡胶弹射入口典型的形态特征,可作为此类损伤的诊断指标。     

Ricochet of a Bullet in the Spinal Canal: A Case Report and Review of the Literature on Bullet Migration

Abstract: Ricochet of a bullet in the spinal canal is well known by neurosurgeons but relatively not a common event in usual medico‐legal autopsy practice. This article presents a homicide case of a penetrating gunshot injury of the lumbar spine through the T12‐L1 intervertebral foramen with active movement of the projectile within the spinal canal to the L5‐S1 level. This case illustrates a bullet intradural and intramedullary active movement because of a ricochet of the body of T12 with active redirection of the path. In the current literature, different types of migration in caudal or cranial direction, intradural, or intramedullary are reported. If spontaneous migration of T10 to S1 seems to be more frequent, some authors reported a C1 to S2 migration. Such migration could be asymptomatic or induce neurological impairment. The medico‐legal consequences of these migrations within the spinal canal are described.     

Intravascular bullet embolism to the right atrium

Bullet embolism is a relatively unusual complication of gunshot wounds. Embolism to the right atrium comprises <5% of all reported intravascular bullet emboli. We report an additional case of bullet embolus to the right atrium of a 0.38-caliber bullet following a gunshot wound to the chest. The intracardiac bullet was recognized radiologically on presentation, but the patient was hemodynamically stable and managed conservatively, with the bullet left in place. The missile remained within the heart without clinical significance for several years and was recovered from the right atrium only at the time of autopsy. To the best of our knowledge, this is the first documented case of a 0.38-caliber bullet which embolized to the right atrium and remained inconsequential for an extended period of time.     

Use of 2D:4D Digit Ratios to Determine Sex

Second to fourth digit ratios (2D:4D) are sexually dimorphic in human hands and established by the 13th gestational week. Application of 2D:4D for determining sex in living individuals by Kanchan et al. (Forensic Sci Int, 181, 2008, 53.e1) produced classification rates of 80% for males and 74–78% for females. Few studies have explored the use of 2D:4D for sexing skeletal remains. We test estimated finger lengths, phalanx lengths, and 2D:4D derived from hand bones for determining sex. Maximum phalanx length was collected using a mini‐osteometric board from 451 individuals of known age, sex, and ancestry in four skeletal collections. Logistic regression of 2nd and 4th digit finger and phalanx lengths produced classification rates greater than 80%. Digit ratios, however, failed to reach classification rates greater than 59%. Our results support those of Voracek (Forensic Sci Int, 185, 2009, e29) and suggest that 2D:4D may be population‐specific and thus inappropriate for universal application as a means of determining sex.     

Use of the global positioning system in the field recovery of scattered human remains

This study examines the Global Positioning System (GPS) as a tool for field mapping of scattered human remains or other materials in forensic investigations. Two aspects of the GPS are considered: (1) the level of accuracy that can be obtained using a mid-priced GPS unit, and (2) the effectiveness of using the GPS to map scattered materials. The positional accuracy of the GPS receiver was tested using a National Geodetic Survey (NGS) point located in Baton Rouge, LA. The utility of the GPS for mapping was investigated by setting up a mock field recovery and mapping the remains using both the GPS and traditional archeological methods. The results indicate that the positional error for a single location using GPS was less than one-half meter. However, when multiple positions were considered, the data produced on different days were not consistent. Further, the GPS receiver used in this study could not distinguish items in close association. Factors such as tree cover density, the proximity of the materials to structures or trees, and satellite positioning contributed to the erratic data. These results indicate that traditional techniques and photographs are still indispensable for mapping scattered remains or artifacts.     

Radiodense bullet wipe around osseous entrance gunshot wounds

“Bullet wipe” is the material deposited by a bullet on any surface with which it comes into contact after it is fired and may contain debris from the gun barrel, including particles of primer and metal fragments from previously fired bullets. X‐ray analysis is a non‐destructive method by which traces of metallic elements can be visually detected. The analysis of osseous defects for radiodense bullet wipe (RBW) assists in determining the presence or absence of perforating gunshot wounds, especially in fragmented, skeletonized remains. The aim of our current study was to determine the frequency of RBW around entrance firearms injuries that perforated bone. We prospectively analyzed entrance gunshot wounds for RBW over a three‐year period using digital X‐ray analysis (n = 59). We retrospectively reviewed the corresponding autopsy reports to determine the frequency of RBW by biologic sex, reported ancestry, age‐at‐death, location of wound, manner of death, range of fire, bullet caliber, and presence of bullet jacket. Data were analyzed by Fisher's exact test or Chi‐square test with significance levels accepted at p < 0.05. RBW was present in 66% (n = 39) of examined cases. Decedent characteristics did not significantly alter RBW distribution, including biologic sex (p = 0.75), reported ancestry (p = 0.49), and age‐at‐death (p = 0.43). Additionally, the location of the osseous entrance gunshot wound, manner of death, range of fire, and cartridge caliber did not affect RBW detection. All cases involving non‐jacketed rounds (n = 5) showed RBW (p = 0.30). To our knowledge, this study is the first to report the frequency of RBW detection from osseous entrance gunshot wounds.     

The Influence of Wood Grain on the Bullet's Ricochet Behavior

When a bullet ricochets from wood, various parameters will influence its behavior. In this study, the influence of the wood grain on the ricochet angle (β) and deflection angle (γ) is assessed. Series of five .32 Auto bullets were fired at different angles of incidence (α) on boards of six wood types. The results confirm the previously shown effect that the mean β‐angles usually exceed α and increase when α increases. Overall, the maximum mean γ occurs when the angle of wood grain (ζ), in relation to the plane of impact, lies between 30° and 75° but differs per combination of wood and α. The results show the inclination of γ toward the left or right, depending on the bullets left or right rotation while also showing that the direction of ζ can enhance or counteract this effect considerably, especially when α is close to the critical ricochet angle.     

Less‐Lethal Hybrid Ammunition Wounds: A Forensic Assessment Introducing Bullet‐Skin‐Bone Entity

Abstract: Agencies all around the world now use less‐lethal weapons with homogeneous missiles such as bean bag or rubber bullets. Contusions and sometimes significant morbidity have been reported. This study focuses on wounds caused by hybrid ammunition with the pathologists’ flap‐by‐flap procedure. Twenty‐four postmortem human subjects were used, and lesions caused on frontal, temporal, sternal, and left tibial regions by a 40‐mm hybrid ammunition (33 g weight) were evaluated on various distance range. The 50% risk of fractures occurred at 79.2 m/sec on the forehead, 72.9 m/sec on the temporal, 72.5 m/sec on the sternum, and 76.7 m/sec on the tibia. Skin lesions were not predictors of bone fracture. There was no correlation between soft and bone tissue observed lesions and impact velocity (correlated to distance range). Lesions observed with hybrid ammunition were the result of bullet‐skin‐bone entity as the interaction of the projectile on skin and bone tissues.     

Case Report of a Migrating Bullet: An Unusual Cause of Postmortem Confusion

Migrating bullets are rare sequelae of penetrating gunshot wounds. Such cases have been described in the neurosurgical literature because they can produce complications in the management of patients such as decline in neurologic status, delays in rehabilitation, and difficulties in bullet removal. In contrast, few postmortem reports have described this phenomenon. We report a case of a gunshot wound in which the projectile entered the left side of the head and traversed to the right frontal area as documented by CT scan on hospital admission. At autopsy, the bullet was noted to have migrated back to the left side of the head from where it was recovered. Medical examiners need to be aware of this unusual phenomenon of retained intracranial projectiles.     

Accuracy and Repeatability of Trajectory Rod Measurement Using Laser Scanners

Three‐dimensional (3D) technologies contribute greatly to bullet trajectory analysis and shooting reconstruction. There are few papers which address the errors associated with utilizing laser scanning for bullet trajectory documentation. This study examined the accuracy and precision of laser scanning for documenting trajectory rods in drywall for angles between 25° and 90°. The inherent error range of 0.02°–2.10° was noted while the overall error for laser scanning ranged between 0.04° and 1.98°. The inter‐ and intraobserver errors for trajectory rod placement and virtual trajectory marking showed that the range of variation for rod placement was between 0.1°–1° in drywall and 0.05°–0.5° in plywood. Virtual trajectory marking accuracy tests showed that 75% of data values were below 0.91° and 0.61° on azimuth and vertical angles, respectively. In conclusion, many contributing factors affect bullet trajectory analysis, and the use of 3D technologies can aid in reduction of errors associated with documentation.