Forensic Conclusions Research Articles

The suitability of visual taphonomic methods for digital photographs: An experimental approach with pig carcasses in a tropical climate

In the context of increased scrutiny of the methods in forensic sciences, it is essential to ensure that the approaches used in forensic taphonomy to measure decomposition and estimate the postmortem interval are underpinned by robust evidence-based data. Digital photographs are an important source of documentation in forensic taphonomic investigations but the suitability of the current approaches for photographs, rather than real-time remains, is poorly studied which can undermine accurate forensic conclusions. The present study aimed to investigate the suitability of 2D colour digital photographs for evaluating decomposition of exposed human analogues (Sus scrofa domesticus) in a tropical savanna environment (Hawaii), using two published scoring methods; Megyesi et al., 2005 and Keough et al., 2017. It was found that there were significant differences between the real-time and photograph decomposition scores when the Megyesi et al. method was used. However, the Keough et al. method applied to photographs reflected real-time decomposition more closely and thus appears more suitable to evaluate pig decomposition from 2D photographs. The findings indicate that the type of scoring method used has a significant impact on the ability to accurately evaluate the decomposition of exposed pig carcasses from photographs. It was further identified that photographic taphonomic analysis can reach high inter-observer reproducibility. These novel findings are of significant importance for the forensic sciences as they highlight the potential for high quality photograph coverage to provide useful complementary information for the forensic taphonomic investigation. New recommendations to develop robust transparent approaches adapted to photographs in forensic taphonomy are suggested based on these findings.

Post-mortem CT imaging of the lungs: pathological versus non-pathological findings.

Nowadays, the modern computed tomography techniques are more and more applied in forensic investigations. The detection of abnormalities in post-mortem computed tomography (PMCT) imaging of the lungs is very common. As in clinical imaging, also in post-mortem imaging the right interpretation of alterations has an extreme importance for the assessment of correct conclusions. This is even crucial when the radiologist who approaches the PMCT images is not routinely involved in forensic cases. The aim of this article is to provide radiologists who approach PMCT imaging cases with some indications for a proper and correct interpretation of pulmonary findings, to avoid misleading forensic conclusions. Particularly, the following issues will be addressed: PMCT imaging of post-mortem changes of the lungs; PMCT imaging of pathological lungs [(a) in thoracic trauma cases, (b) in cases without thoracic trauma]. Finally, the possible pitfalls in interpretation of PMCT imaging of the lungs will be also discussed.

Forensic Science Accuracy: Why We Know Little and How to Learn More

Forensic science – which includes such techniques as DNA analysis, fingerprint examination, and firearms comparison – plays a crucial role in our criminal justice system by helping to convict the guilty and acquit the innocent. However, our confidence in forensic science conclusions must be tempered by the odds that those conclusions are wrong. What are those odds? Nobody knows the answer because no disinterested researchers have conducted the appropriate studies in any of the forensic science disciplines. This is a serious problem because, without this information, legal decision makers cannot properly assess the validity or probative value of forensic evidence. In this paper, I examine the institutional forces and misunderstandings that are responsible for our ignorance about the accuracy of forensic science conclusions. I then recommend a new type of proficiency testing regimen (Type II proficiency testing) that is designed to measure error rates under appropriate test conditions in the various forensic subfields. Unless and until such studies are undertaken, legal decision makers will continue to fly blind when it comes to assessing the reliability of a reported forensic match.

Epistemology applied to conclusions of expert reports

It is believed that to build a robust reasoning logic to make probabilistic inferences in forensic science from a merely mathematical or logistical viewpoint is not enough. Mathematical logic is the positive science of reasoning and as for that it is only interested in the positive calculus of its validity, regardless any prior ontological assumption. But without a determined ontology and epistemology which imply to define the concepts that they will use, it seems difficult that the proposed scientifically correct mathematical solution be successful as a European standard for making conclusions in forensic reports because it has to be based on judicial language.Forensic experts and Courts are not interested in the development of a positive science but in a practical science: in clarifying whether certain known facts are related to a possible crime. Therefore, not only the coherence of the demonstrative logic reasoning used (logic of propositions) is important, but also the precision of the concepts used by language and consistency among them in reasoning (logic of concepts).There is a linguistic level essential for a successful communication between the forensic practitioner and the Court which is mainly related, in our opinion, to semantics and figures of speech. The first one is involved because words used in forensic conclusions often have different meanings – it is said that they are polysemic – and the second one because there is often metonymy as well. Besides, semantic differences among languages regarding words with the same etymological root add another difficulty for a better mutual understanding.The two main European judicial systems inherit a wide and deep culture related to evidence in criminal proceedings and each of them has coined their own terminology but there are other two more abstract levels such as logical and epistemological, where we can find solid arguments by which terms used at legal level on conclusions of forensic reports could be accurate and consistent for all users of an intended EU guideline. An effort has been made to elucidate the following terms: truth, certainty, uncertainty, opinion, conjecture, probability, evidence, belief, credibility, determinism, indeterminacy, cause, principle, condition, and occasion.

Consequences of Decontamination Procedures in Forensic Hair Analysis Using Metal-Assisted Secondary Ion Mass Spectrometry Analysis.

Today, hair testing is considered to be the standard method for the detection of chronic drug abuse. Nevertheless, the differentiation between systemic exposure and external contamination remains a major challenge in the forensic interpretation of hair analysis. Nowadays, it is still impossible to directly show the difference between external contamination and use-related incorporation. Although the effects of washing procedures on the distribution of (incorporated) drugs in hair remain unknown, these decontamination procedures prior to hair analysis are considered to be indispensable in order to exclude external contamination. However, insights into the effect of decontamination protocols on levels and distribution of drugs incorporated in hair are essential to draw the correct forensic conclusions from hair analysis; we studied the consequences of these procedures on the spatial distribution of cocaine in hair using imaging mass spectrometry. Additionally, using metal-assisted secondary ion mass spectrometry, we are the first to directly show the difference between cocaine-contaminated and user hair without any prior washing procedure.

Nuclear forensic analysis of uranium oxide powders interdicted in Victoria, Australia

Abstract Nuclear forensic analysis was conducted on two uranium samples confiscated during a police investigation in Victoria, Australia. The first sample, designated NSR-F-270409-1, was a depleted uranium powder of moderate purity (∼ 1000 μg/g total elemental impurities). The chemical form of the uranium was a compound similar to K2(UO2)3O4 · 4H2O. While aliquoting NSR-F-270409-1 for analysis, the body and head of a Tineid moth was discovered in the sample. The second sample, designated NSR-F-270409-2, was also a depleted uranium powder. It was of reasonably high purity (∼ 380 μg/g total elemental impurities). The chemical form of the uranium was primarily UO3 · 2H2O, with minor phases of U3O8 and UO2. While aliquoting NSR-F-270409-2 for analysis, a metal staple of unknown origin was discovered in the sample. The presence of 236U and 232U in both samples indicates that the uranium feed stocks for these samples experienced a neutron flux at some point in their history. The reactor burn-up calculated from the isotopic composition of the uranium is consistent with that of spent fuel from natural uranium (NU) fueled Pu production. These nuclear forensic conclusions allow us to categorically exclude Australia as the origin of the material and greatly reduce the number of candidate sources.

Subdural hygromas in abusive head trauma: pathogenesis, diagnosis, and forensic implications.

Are subdural hygromas the result of abusive head trauma? CT and MR imaging represent important tools for the diagnosis of abusive head trauma in living infants. In addition, in-depth understanding of the pathogenesis of subdural hygromas is increasingly required by neuroradiologists, pediatricians, and forensic physicians. Therefore, the current knowledge on subdural hygromas is summarized and forensic conclusions are drawn. The most important diagnostic pitfalls, benign enlargement of the subarachnoid space, and chronic subdural hematoma, are discussed in detail. Illustrative cases from forensic practice are presented. Literature analysis indicates that subdural hygromas can occur immediately or be delayed. If other infrequent reasons can be excluded, the presence of subdural hygromas strongly suggests a posttraumatic state and should prompt the physician to search for other signs of abuse. To differentiate subdural hygromas from other pathologies, additional MR imaging of the infant's head is indispensable after initial CT scan.

Sexual Offenses Against Elderly People: Forensic Evaluation and Judicial Outcome

Forensic evaluation reports and judicial outcomes regarding older victims of suspected sexual offenses were retrospectively reviewed. During this period, a total of 14 cases were registered, corresponding to 0.3% of nonfatal crimes against elderly and 0.6% of the total of sexual crimes reported. All the victims were female. The majority lived alone and did not have limitations in communication, orientation, ambulation, or autonomy. The offenders were all male (17 to 81 years old); most were known to the victims and had history of previous disruptive behaviors. The majority of the sexual offenses occurred in the victims’ homes, and the offenders tended to use physical violence. Forensic evaluation was crucial for the identification of physical and biological evidence, and forensic conclusions were positively correlated with the judicial outcome of each case. High prosecution and conviction rates were also observed.

Errors in forensics: Cause(s) and solutions

Authors Kassin, Dror, and Kukucka speculate on causes underying forensic errors in their article, “The forensic confirmation ias: Problems, perspectives, and proposed solutions” (2013). The uthors highlight that forensic conclusions are less reliable than nce assumed. This not only applies to the less well-known forensic isciplines, like hair analysis, bite mark analysis and arson investiation, but also to the most trusted disciplines, such as fingerprint omparison and DNA analysis. Although fingerprint analysis has een used for over 100 years, errors affecting the lives of innocent eople have occurred, making it necessary to investigate causes nd implement effective corrective action. The article suggests that bias and subjectivity are the root cause f many errors and then suggests remedies for such problems. The ecommendations include performing an examination in a linear anner with a full analysis of data prior to comparing the evidence o a known exemplar, blinding analysts from certain information, nd more comprehensive documentation of information known nd relied on during the examination process. As stated in the artile, these recommendations are not new; they have been previously uggested and implemented by some agencies. On the surface, the suggested reasons and associated recmmendations for errors sound reasonable; however, errors in orensics are a new area of research and as such, have not yet een fully explored. Other causes for errors need to be considred. Past research has been performed which hypothesized that ias and subjectivity cause errors. Subsequently, experiments were erformed to verify these beliefs. This type of research shows a cor-

Can clinical CT data improve forensic reconstruction?

In accidents resulting in severe injuries, a clinical forensic examination is generally abandoned in the initial phase due to high-priority clinical needs. However, in many cases, data from clinical computed tomography (CT) examinations are available. The goals of this prospective study were (a) to evaluate clinical CT data as a basis for forensic reconstruction of the sequence of events, (b) to assess if forensic radiological follow-up reading improves the forensic diagnostic benefit compared to the written clinical radiological reports, and (c) to evaluate if full data storage including additional reconstructed 0.6-mm slices enhances forensic analysis. Clinical CT data of 15 living individuals with imaging of at least the head, thorax, and abdomen following polytrauma were examined regarding the forensic evaluation of the sequence of events. Additionally, 0.6-mm slices and 3D images were reconstructed for forensic purposes and used for the evaluation. At the forensic radiological readings, additional traumatic findings were observed in ten of the 15 patients. The main weakness of the clinical reports was that they were not detailed enough, particularly regarding the localization of injuries and description of wound morphology. In seven cases, however, forensic conclusions were possible on the basis of the written clinical reports, whereas in five cases forensic reconstruction required specific follow-up reading. The additional 0.6-mm slices were easily available and with improved 3D image quality and forensic diagnostics. In conclusion, the use of clinical CT data can considerably support forensic expertise regarding reconstruction issues. Forensic follow-up reading as well as the use of additional thin slices for 3D analysis can further improve its benefit for forensic reconstruction purposes.

One small scan for radiology, one giant leap for forensic medicine – Post-mortem imaging replaces forensic autopsy in a case of traumatic aortic laceration

The questions of cause and manner of death are the most pressing ones in any forensic investigation. Traditionally, autopsy is the means to provide answers to these questions and despite the increasing use of CT and MR in the post-mortem setting, imaging has usually been an adjunct to forensic autopsy. Here we describe a case where post-mortem CT and MR were performed instead of autopsy, at the request of the responsible public prosecutor. The forensic conclusions derived from imaging, including cause and manner of death were accepted by the legal authorities, thereby setting precedence for future cases. This case represents a landmark in forensic medicine and is another step toward the full realization of minimally invasive forensic autopsy.

3D bloodstain pattern analysis: Ballistic reconstruction of the trajectories of blood drops and determination of the centres of origin of the bloodstains

For crime scene investigation in cases of homicide, the pattern of bloodstains at the incident site is of critical importance. The morphology of the bloodstain pattern serves to determine the approximate blood source locations, the minimum number of blows and the positioning of the victim. In the present work, the benefits of the three-dimensional bloodstain pattern analysis, including the ballistic approximation of the trajectories of the blood drops, will be demonstrated using two illustrative cases. The crime scenes were documented in 3D, using the non-contact methods digital photogrammetry, tachymetry and laser scanning. Accurate, true-to-scale 3D models of the crime scenes, including the bloodstain pattern and the traces, were created. For the determination of the areas of origin of the bloodstain pattern, the trajectories of up to 200 well-defined bloodstains were analysed in CAD and photogrammetry software. The ballistic determination of the trajectories was performed using ballistics software. The advantages of this method are the short preparation time on site, the non-contact measurement of the bloodstains and the high accuracy of the bloodstain analysis. It should be expected that this method delivers accurate results regarding the number and position of the areas of origin of bloodstains, in particular the vertical component is determined more precisely than using conventional methods. In both cases relevant forensic conclusions regarding the course of events were enabled by the ballistic bloodstain pattern analysis.

Virtual and macroscopical studies of mummies—Differences or complementarity? Report of a natural frozen Siberian mummy

Since 2004, a multidisciplinary Franco-Russian expedition discovered in the Sakha Republic (Yakutiya) more than 60 tombs preserved by the permafrost. In July 2006, an exceptionally well-preserved mummy was unearthed. The coffin, burial furniture and clothes suggested a shaman's tomb. Multislice computed tomography (MSCT) was performed before autopsy with forensic and anthropological aims. Forensic study aimed to detect any lesions and determine the manner of death. Anthropological study aimed to determine the mummy's gender, age at death, morphological affinity, stature and body mass. She was female and virginity status was assessed. The radiological and forensic conclusions were compared. Imaging confirmed most autopsy findings, suggesting that death followed disseminated infection. MSCT could not formally exclude a traumatic death because close examination of the skin was difficult, but was superior to conventional autopsy in diagnosis of infectious lesions of the left sacroiliac joint and one pelvic lesion. Autopsy detected a post-infectious spinal lesion, misinterpreted on MSCT as a Schmorl's node. However, most conclusions of virtual and conventional anthropological studies agreed. Age at death was estimated around 19 years old. The morphology of the mummy was mongoloid. MSCT identified the craniometric characteristics as similar to those of the Buryat population. The deceased's stature was 146 cm and estimated body mass was 49 kg. MSCT demonstrated its great potential and complementarity with conventional autopsy and anthropological techniques in the study of this natural female mummy buried in 1728.

Examinee-Reported History Is Not a Credible Basis for Clinical or Administrative Decision Making

Abstract If a patient reports not having back pain before lifting an object at work but having chronic disabling pain thereafter, an examiner may conclude without further questioning that an injury took place when the object was lifted and therefore is work related. This article reviews relevant scientific findings and provides recommendations for making disability determinations in a manner that is more credible than basing conclusions on an examinee's reports. The author specifically recommends that future editions of the AMAGuides to the Evaluation of Permanent Impairment (AMA Guides) should emphasize that clinical and forensic conclusions cannot be based on reports from an examinee and instead must be based on more credible sources of information. Research has shown that, among individuals who believe that a specific event (eg, an accident) caused the current complaints, the individual is likely to underreport their health history for the time preceding that event and to overstate the extent of their problems following the event. Other researchers found that claimants systematically underreported every preclaim health issue that might have provided a non–injury-related explanation for their complaints. Any basis for a conclusion of injury should be based on objective and scientifically credible findings that would have indicated that an injury had occurred even in the absence of any information having been reported by the patient.

Physicists in forensics

From faulty products to murder, physicists help figure out what really happened.

A metallurgical review of the interpretation of bullet lead compositional analysis

Comparison of the minor and trace element compositions of bullet lead alloys has been used by some forensic examiners to make definitive positive associations between bullets or lead fragments at a crime scene and samples of bullets linked to a suspect(s). Such conclusions have been based on the elemental analysis of isolated groups of bullets with no consideration of the metallurgical processes involved in the production and refining of the bullet lead alloys. An understanding of the metallurgy of lead refining reveals that the elements quantified in the forensic analysis are carefully controlled in the refining process and that there are logical reasons why some elements are more discriminatory than others. Data for lead alloys supplied to two major ammunition manufacturers confirm that multiple indistinguishable shipments of lead alloys from secondary lead refiners to the ammunition manufacturers are made each year and over a period of many years. The data also demonstrate that distinguishable compositions can come from the same melt or “source” of lead alloy. These results clearly indicate that bullets with indistinguishable compositions could have come from different lead “sources” produced in the same or different years. Furthermore, the observation that two bullets have a distinguishable composition does not necessarily mean that they came from a different “source”. Our results show that the forensic examiner using a method of bullet lead alloy elemental analysis, which quantifies up to six elements is restricted to concluding only that indistinguishable bullets might have come from the same “source,” not that they did come from the same “source”. In addition, it is quite possible that multiple bullets with similar but distinguishable compositions could have come from the same “source”. The authors therefore feel that there is no scientific validity to any conclusions more positive than attributing the possible association as to molten source among bullets from different samples. An understanding of the metallurgical principles operative in the melting/casting process as well as the data acquired for this study, indicate that any forensic conclusions which associate unknown bullets with the “same source”, and/or “same box” should fail most or all Daubert criteria.

Thiopentalkonzentrationsverlauf im Vollblut von schwangeren und nichtschwangeren Patientinnen in den ersten Minuten nach der Injektion

Thiopentone concentrations in blood following injection of the induction solution (Thiopental, 2.5%) may be critical in the context of lethal complications arising during induction of anaesthesia and thereby the toxicological aspects of this drug can become an issue in forensic considerations. The study was designed to find out whether the dose of injected thiopentone may be calculated from blood levels measured in nine pregnant and ten non-pregnant patients. The doses injected ranged from 4-5 mg per kg body weight. The drug was administered as a single bolus dose to the patients undergoing Caesarean section. In the non-pregnant group the first dose of thiopentone was given over 25 s. After that repeated doses of 50 mg were injected over 2s every 20s until the eyelid reflex was ceased. Blood samples for determination of thiopentone were withdrawn from an indwelling catheter inserted to a large cubital vein in the arm opposite that used for the injection and thiopentone levels were measured from blood after column extraction (Extrelut) using spectrophotometry. Venous peak values were found 40-115s after injection in the Caesarean group (mean: 20.3 micrograms kg-1) and were higher than in the non-pregnant patients (97-190s, mean: 17.8 micrograms kg-1). No correlation was found regarding venous peak levels (mgkg-1 blood) and induction dose (mgkg-1 body weight), neither in the pregnant nor in the non-pregnant group. Our findings would suggest that the injected thiopentone dose cannot be calculated from the concentration of the drug in the blood. Forensic conclusions concerning the onset of lethal complications during the induction of anaesthesia cannot be drawn on the grounds of venous thiopentone concentrations.

Forensic analysis of blood-splash patterns

Although certain textbooks of Forensic Pathology include photographs which show the splash patterns of drops of blood falling from greater or lesser heights or from a moving source, the literature is almost devoid of detailed scientific data relating to this; yet such information could be of great importance to forensic medicine in the reconstruction of a crime. Blood-stain patterns made by a single drop of blood falling vertically were investigated. Physical measurements of these stains were used to determine the relationships between the height of fall, the volume of the drop and the final area of the splash, but only under very particular laboratory conditions. High speed cinematographic films of splashing drops were used to determine the way in which splash patterns were produced. Variables which influenced the area of spread of a vertically falling drop included the roughness of the surface on to which the blood had fallen, the atmospheric temperature, the haemoglobin content of the blood, and its viscosity. Only by setting up an experiment rigorously reproducing the conditions of a crime, which would seldom be possible, could an accurate assessment be made of the height of fall of a splashed drop of blood. One should be very cautious in drawing forensic conclusions from blood-splash patterns. Although certain textbooks of Forensic Pathology include photographs which show the splash patterns of drops of blood falling from greater or lesser heights or from a moving source, the literature is almost devoid of detailed scientific data relating to this; yet such information could be of great importance to forensic medicine in the reconstruction of a crime. Blood-stain patterns made by a single drop of blood falling vertically were investigated. Physical measurements of these stains were used to determine the relationships between the height of fall, the volume of the drop and the final area of the splash, but only under very particular laboratory conditions. High speed cinematographic films of splashing drops were used to determine the way in which splash patterns were produced. Variables which influenced the area of spread of a vertically falling drop included the roughness of the surface on to which the blood had fallen, the atmospheric temperature, the haemoglobin content of the blood, and its viscosity. Only by setting up an experiment rigorously reproducing the conditions of a crime, which would seldom be possible, could an accurate assessment be made of the height of fall of a splashed drop of blood. One should be very cautious in drawing forensic conclusions from blood-splash patterns.