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.     

物证鉴定证据应用层级论

用物证鉴定结论证明犯罪需要经过推理过程,将物证来源鉴定结论转化为嫌疑人行为推论,后者再作为法律事实证明嫌疑人是否有罪。物证鉴定证据应用的递进证明关系,可以用由依次推理关系连接的物证来源结论层、行为推论层和定罪层构成的物证鉴定层级模型描述。该模型可直观表达和评估物证鉴定结论证据应用效力。     

A validation study for duct tape end matches

Fracture matches are considered to be the strongest association achievable in forensic examinations of glass, metal, wood, plastic, paint, tape, and other trace evidence. Despite being fairly routine examinations, few publications exist to support their admissibility in court. This study was designed, using duct tape as the fractured medium, to determine the validity and error rate associated with conducting end match (fracture match) examinations on this material. Five test designs, which varied either the source roll of tape or manner of separation (torn or cut) from the roll, were administered to four analysts with instructions to examine the assigned test sets for end matches. If an end match was not identified by the initial analyst, the entire test set was independently evaluated by the remaining three analysts. Results indicated that while tape grade did not hinder end match identification, the manner of separation could affect results.     

Investigation of Ballistic Evidence through an Automatic Image Analysis and Identification System

Automated firearms identification (AFI) systems contribute to shedding light on criminal events by comparison between different pieces of evidence on cartridge cases and bullets and by matching similar ones that were fired from the same firearm. Ballistic evidence can be rapidly analyzed and classified by means of an automatic image analysis and identification system. In addition, it can be used to narrow the range of possible matching evidence. In this study conducted on the cartridges ejected from the examined pistol, three imaging areas, namely the firing pin impression, capsule traces, and the intersection of these traces, were compared automatically using the image analysis and identification system through the correlation ranking method to determine the numeric values that indicate the significance of the similarities. These numerical features that signify the similarities and differences between pistol makes and models can be used in groupings to make a distinction between makes and models of pistols.     

Distinguishing between homicide and suicide knots and ligatures: A comparative analysis of case and survey data

Distinguishing between suicide and homicide can be challenging owing to ambiguous and confusing case details. In particular, there is a paucity of useful information comparing homicide and suicide knots and ligatures in the literature. Multiple knot and ligature characteristics have not been recognized previously because complete and accurate information has been lacking. Ninety external tying cases (mainly homicide) and 56 cases involving self‐tying (mainly suicide) were reviewed to compare multiple knot and ligature characteristics. Additionally, 189 survey volunteers performed four standardized external tying tasks and two self‐tying tasks, yielding comparison data from more than 1500 knots. Using all available data, it was determined that the differences between external and self‐tying included types of knots, ligature configurations, ligature tensions, wrist gaps, wend lengths, knot access, external anchoring, and other indicators. These differences are presented in a proposed analysis checklist inspired by medical and psychiatric protocols. The checklist contains 14 potential characteristics for head and neck bindings, 14 potential characteristics for wrists and arms, nine ankle and leg characteristics, and four linkage details. The proposed checklist can be expanded and fine‐tuned as more data are accumulated. It offers experienced knot analysts an additional tool to assist in drawing conclusions, which then can be related to other case evidence by investigators.     

Uniqueness of the Dentition as Impressed in Human Skin: A Cadaver Model*

Abstract: Bitemark interpretation assumes that the human dentition is unique and that its attributes can be accurately transferred to skin. A cadaver model was used to investigate whether the correct biter could be determined from similarly aligned dentitions once the dentitions were impressed in human skin. One‐hundred dental stone models, which were measured and determined to be unique, were divided into 10 groups based upon similarities of mal‐alignment patterns. One model was randomly selected from each group and bites were produced on unembalmed human cadavers. Metric/angular measurements and hollow volume overlays of the models were compared with the bites made. The percentage of dentitions from each group as well as the 100 dental model population that could not be excluded as the biter was determined. Results showed difficulty distinguishing the biter from individuals with similarly aligned dentitions and in some cases, an incorrect biter appeared better correlated to the bite.     

Suicide by Fatal Pentobarbital Intoxication in Ontario,Canada, from 2012 to 2015

A fatal concentration of pentobarbital found in a coroner's case where the history had not indicated use of this drug prompted a review of fatalities in Ontario from 2012 to 2015. Coroner's case files, including police and toxicology reports, were reviewed in twenty deaths, in which pentobarbital was identified as the primary cause of death. In all of the deaths (11 females, 9 males), the blood concentration of pentobarbital was greater than 10 mg/L. There were three to eight deaths per year and each was classified as suicide. In 11 cases, there was clear evidence that the drug was purchased over the internet from Mexico or China and imported into Canada. In four cases, it appears that the pentobarbital was labeled as a different, innocuous chemical to facilitate crossing the border without scrutiny. The findings underscore the value of a thorough scene investigation, including details of evidence that may be considered unrelated.     

Human Identification Using Automatic and Semi‐Automatically Detected Facial Marks

Continuing advancements in the field of digital cameras and surveillance imaging devices have led law enforcement and intelligence agencies to use analysis of images and videos for the investigation and prosecution of crime. When determining identity from photographic evidence, forensic analysts perform comparison of visible facial features manually, which is inefficient. In this study, we will address research efforts to use facial marks as biometric signatures to distinguish between individuals. We propose two systems to assist forensic analysts during photographic comparison: an improved multiscale facial mark system in which facial marks are detected automatically, and a semi‐automatic facial mark system that integrates human knowledge within the improved multiscale facial mark system. Experiment results employ a high‐resolution time‐elapsed dataset acquired at the University of Notre Dame between 2009 and 2011. The results indicate that the geometric distributions of facial mark patterns can be used to distinguish between individuals.     

论毒品犯罪案件的证据

毒品犯罪案件有许多不同于普通刑事案件的特殊性,毒品案件中的证据又具有相对的单一性,必须当场缴获毒品和毒资才能证实犯罪。本文结合缉毒侦查中的具体情况,强调办理毒品案件必须增强证据意识,要把握好破案的时机,适时取证;收集证据一定要十分仔细,获取的证据应做好固定保全工作,并特别注意取证的合法性;采用技术侦察手段须把握住一条底线:不得诱人犯罪;应正确运用推定规则判定"明知",对推定结论允许以确凿的事实予以反驳。     

A validation study for vinyl electrical tape end matches

Fracture matches are considered the strongest conclusion in the forensic examination of rigid materials, such as glass, metal, and paint. However, publications that support the fracture matching of polymeric films, such as tape backings, are limited. This study was designed to determine the validity and error rate associated with conducting end-match (fracture match) examinations on vinyl electrical tape. Test designs varied the source roll of tape, test preparer, or mode of separation from the roll. Results indicated that each affected the resulting severed tape ends. The analysts examining the end matches also had an effect on the results. Eight end matches in the study were not identified by the initial analysts and were considered inconclusive. One end match was misidentified, resulting in one false positive and an error rate of 0.049%. These results support a comprehensive physical and chemical tape comparison regardless of indications of an end match.     

The Importance of Blind Forensic Odontology Analyses

Forensic odontology cases examined from 2012 to 2019 at the Defense POW/MIA Accounting Agency (DPAA) laboratory were reviewed. Five cases from World War II and the Korea War were selected. Three of the cases presented involve dental assemblages, which were built by previous analysts. Postmortem radiographic analyses at the DPAA laboratory of these cases were complicated by the use of an older version of a digital x-ray program and the assumption that teeth placed in the parent bone (maxilla and mandible) did not fully articulate due to the presence of debris at their root apices. Conflicting mitochondrial DNA test results for the submitted teeth and previously believed to be parent bone indicated these elements were not from the same individual. The remaining two cases are examples of how knowledge of findings from other disciplines may sway an opinion and could possibly lead to the rendering of erroneous opinions by the forensic odontologist. Having knowledge of previous examinations or results from other scientists, disciplines, and lines of evidence may lead to a bias in findings or opinions. If not careful, even the best-intended scientist may fall victim to a bias in their opinion/analysis. The forensic odontologist should perform all analysis in the blind, not knowing any information which may bias their opinion, and utilize current versions of digital x-ray software available and their tools when performing their examinations.     

Automated SEM/EDS Analysis of Airbag Residue.* I: Particle Identification

Abstract: Deployed airbags can be a valuable source of probative forensic materials. During an accident, trace evidence can be deposited on the airbag cover and in addition, the residue produced by the gas generation system is released into the passenger compartment of the vehicle as the airbag deflates. This residue can be used to associate a suspect with the vehicle at the time of the accident. This study identifies particles containing zirconium, strontium, and/or copper–cobalt along with other elements from the gas generation systems and aluminum silicon microfibers from airbag filters as the probative material which may be produced and deposited on a suspect’s hands and/or clothing. Scanning electron microscopy can be used to identify this metallic residue. Modification of the search criterion used for gunshot residue analysis allows for automated analysis of the samples. Proper collection of the airbag standard is essential to identify which materials were produced. Prompt collection of suspect samples allows the analysts the ability to make the proper identifications and associations. This analytical technique can be a probative tool in criminal investigations.     

Implementation of a Blind Quality Control Program in a Forensic Laboratory

A blind quality control (QC) program was successfully developed and implemented in the Toxicology, Seized Drugs, Firearms, Latent Prints (Processing and Comparison), Forensic Biology, and Multimedia (Digital and Audio/Video) sections at the Houston Forensic Science Center (HFSC). The program was put into practice based on recommendations set forth in the 2009 National Academy of Sciences report and is conducted in addition to accreditation required annual proficiency tests. The blind QC program allows HFSC to test its entire quality management system and provides a real-time assessment of the laboratory’s proficiency. To ensure the blind QC cases mimicked real casework, the workflow for each forensic discipline and their evidence submission processes were assessed prior to implementation. Samples are created and submitted by the HFSC Quality Division to whom the expected answer is known. Results from 2015 to 2018 show that of the 973 blind samples submitted, 901 were completed, and only 51 were discovered by analysts as being blind QC cases. Implementation data suggests that this type of program can be employed at other forensic laboratories.     

An Unusual Case of Predation: Dog Pack or Cougar Attack?

Injuries produced by animals are capable of leaving severe patterns and in some cases may result in the death of the attacked individual. Law enforcement authorities may come to erroneous conclusions about the source of the bites based on their awareness of animals present and similarities of the injuries to the untrained eye, with dreadful consequences. Expertise of a carnivore biologist and an odontologist that indentifies the particularities of bite marks may be useful for identifying the attacking species. We present the investigation of a fatal dog pack attack involving a 43‐year‐old man in Bell Ville (Argentina) where the evidence provided by a forensic dentist and a biologist was categorical for establishing the animal species involved. Because of the unusual characteristics of the wounds and the initial hypothesis made by local authorities of a cougar attack, habits and specific patterns of both dog pack and cougar predation on humans are discussed.     

Tables for the Metric Evaluation of Pair‐Matching of Human Skeletal Elements

A common task in forensic anthropology involves pair‐matching of left and right skeletal elements. This can be achieved through visual pair‐matching by evaluating similarities in morphology, and through osteometric sorting, a quantitative technique. To simplify the process of osteometric sorting, this article explains the use of a statistic (M), which captures the amount of size variation found between homologous bones from single individuals. A database of skeletal measurements for all major paired postcranial bones is used to calculate values of M from a variety of sources. The maximum value and the 90th and 95th percentiles of M are provided in tabular format, and values of M from forensic cases can be compared to these tables as an objective means for determining whether homologous bones could have originated from the same individual. This simple technique can be combined with visual pair‐matching to be particularly effective in cases involving commingling of skeletons.     

(Re)configuring the criminal justice response to human trafficking: a complex-systems perspective

Abstract

The multidimensional complexities associated with the criminal justice response to human trafficking are well documented. The transient and subversive nature of human trafficking as organised crime and the large number of multidisciplinary role-players involved in coordinating cross jurisdictional efforts to prevent, investigate and prosecute such cases, contribute to this complex undertaking. Complex systems theory suggests that a complex social problem such as human trafficking cannot be approached by using a linear or simplified lens, and requires a holistic perspective on the complex interactions between actors, and emergent behaviour in both the criminal justice system and the human trafficking system that it seeks to combat. This paper explores the characteristics of complexity, and uses illustrations from the lived experiences of actors in South Africa’s efforts to combat human trafficking, in order to demonstrate how complex systems theory could be considered and integrated into the criminal justice response to human trafficking.     

Suicide and Psychiatrist's Liability in Italian Law Cases

The aim of the study is to analyze the factors that are most frequently associated with a verdict of guilty delivered to the psychiatrist in cases of a patient's suicide in Italian law. Twenty‐six sentences (1975–2009) were analyzed according to the claim of malpractice, patient characteristics, circumstances of the suicide, and reasons for the court's judgment. The court held the psychiatrist guilty in 12 cases, considering that the act of suicide was predictable and could have been avoided. Predictability was mainly related to errors in surveillance (7 cases), therapy (1 case), or both (2 cases). An error in diagnosis was considered to be related to the patient's death in two cases. Analysis of medical behavior considered to be erroneous and associated with a verdict of guilty provides an opportunity to discuss the topics relevant not only to practicing psychiatrists but also to experts assessing medical liability in cases of patient suicide.     

Modeling Bone Surface Morphology: A Fully Quantitative Method for Age‐at‐Death Estimation Using the Pubic Symphysis

The pubic symphysis is widely used in age estimation for the adult skeleton. Standard practice requires the visual comparison of surface morphology against criteria representing predefined phases and the estimation of case‐specific age from an age range associated with the chosen phase. Known problems of method and observer error necessitate alternative tools to quantify age‐related change in pubic morphology. This paper presents an objective, fully quantitative method for estimating age‐at‐death from the skeleton, which exploits a variance‐based score of surface complexity computed from vertices obtained from a scanner sampling the pubic symphysis. For laser scans from 41 modern American male skeletons, this method produces results that are significantly associated with known age‐at‐death (RMSE = 17.15 years). Chronological age is predicted, therefore, equally well, if not, better, with this robust, objective, and fully quantitative method than with prevailing phase‐aging systems. This method contributes to forensic casework by responding to medico‐legal expectations for evidence standards.