A comparison of three shoe sole impression lifting methods at high substrate temperatures

Footwear impressions are a common form of evidence found at crime scenes, and the accurate recovery and recording of such impressions is critical for shoe sole comparison and identification. The lifting of shoe sole impressions from hot surfaces (>30°C/86°F) and in hot environments has received little attention in the literature, particularly in relation to the recovery of class and randomly acquired characteristics (RACs) required for accurate comparisons. This study addressed this knowledge gap by comparing the performance of three common impression lifters (gelatin, adhesive, and vinyl static cling film) at recovering shoe sole impressions in dust from hot flooring substrates. Dry origin dust shoe sole impressions were made on ceramic tile, galvanized metal, and laminated wood flooring using a shoe that possessed two RACs and five class characteristics present on the sole. Substrates were left in direct full sun for five hours during a summer day prior to lifting. Performance was measured by the proportion of RACs and class characteristics visible in each lifted impression. Results demonstrated that the vinyl static cling film tested performed poorly across all substrates, particularly for metal (23.8% marks recovered), including notable shrinkage of the lifted impression. In contrast, adhesive (~96% marks recovered over all substrates), and to a lesser extent gelatin (~85%), lifts were highly successful on hot substrates. These data suggest that adhesive lifts can consistently and accurately recover shoe sole impressions from hot substrates. This study contributes critical information for crime scene examiners to improve and expand evidence recovery in hot environments.     

Denial of pregnancy and neonaticide: A historical overview and case report

While denial of pregnancy and neonaticide are rare, they are potentially associated and share some risk factors. Neonaticide has been proposed as the extreme outcome of a denial of pregnancy. However, the process leading to such a possible outcome is not yet fully understood. The primary goal of this essay is to examine the various definitions and ambiguities surrounding the denial of pregnancy. The case of a young woman with a history of two denied pregnancies with diverse characteristics and outcomes, the latest of which resulted in neonaticide, is then reported and examined. A forensic psychiatric evaluation was also performed to reconstruct the woman's mental state at the time of the crime. The forensic pathological analysis of the newborn, abandoned near the sea while still alive, is described. The victim's body showed signs of shaken baby syndrome. We contend that differing levels of awareness during a denial of pregnancy might not be predictive of the potential delivery outcome in terms of threat to the newborn's survival, according to the forensic pathological and psychopathological data of the current case. Early identification of women affected by denial of pregnancy who pose a danger of committing infanticide is hampered by both intrinsic traits (dissimulation, unawareness, low propensity to seek assistance) and environmental factors (isolation, low socioeconomic level, poor education.). A previous history of denial of pregnancy should activate health and support services to reduce the potential risks for the mother and the child.     

Photographic comparison of surface topography as a viable solution when physical match is challenging

Physical matching methods are a family of well‐known methods that are utilized in order to determine whether two pieces of a tearable/breakable material used to be one object. When performing physical match of polymers, it is sometimes difficult to reach an unambiguous conclusion. This is due to various reasons. One is when the tear/fracture resides in an inaccessible or hidden‐from‐view region of the piece. Another is when the shape of the tear/fracture at the object's tear/fracture line is insufficient for deducing a complete match. Third is deficiency of material along this line. These are examples of processes where the line is affected so drastically, so that a match renders impossible. Specifically, when addressing elastic materials, the tear/fracture line may even be squashed. This may also be a reason for difficulty in performing a physical match. In this paper, a method is proposed where a match is alternatively achieved by means of photographic comparison of marks on the surface topography of the pieces‐in‐question. Comparisons of pairs of torn pieces of silicon rubber were made. The procedure involved photography of the surface topography the pieces. Then, the photographs were horizontally mirror‐flipped. Lastly, a comparison was made between two photographs: a photograph of one piece and a mirror‐flipped photograph of the opposite piece. The results show that after comparing the pieces to one another, only one unique pair turned out to be positively matched. Using the proposed method, not only the comparison is done by a more informative method (comparing to physical match), it is also more convenient, faster, less expensive, and technically simpler.     

Relevance analysis using revision identifier in MS word

Electronic documents often contain personal or confidential information, which can be used as valuable evidence in criminal investigations. In the digital investigation, special techniques are required for grouping and screening electronic documents, because it is challenging to analyze relationships between numerous documents in storage devices manually. To this end, although techniques such as keyword search, similarity search, topic modeling, metadata analysis, and document clustering are continually being studied, there are still limitations for revealing the relevance of documents. Specifically, metadata used in previous research are not always values present in the documents, and clustering methods with specific keywords may be incomplete because text‐based contents (including metadata) can be easily modified or deleted by users. In this work, we propose a novel method to efficiently group Microsoft Office Word 2007+ (MS Word) files by using revision identifier (RSID). Through a thorough understanding of the RSID, examiners can predict organizations to which a specific user belongs, and further, it is likely to discover unexpected interpersonal relationships. An experiment with a public dataset (GovDocs) provides that it is possible to categorize documents more effectively by combining our proposal with previously studied methods. Furthermore, we introduce a new document tracking method to understand the editing history and movement of a file, and then demonstrate its usefulness through an experiment with documents from a real case.     

Reporting likelihood ratio for casework in firearm evidence identification

Likelihood ratio (LR) plays an important role in estimating the weight of evidence in firearm evidence identifications. LR is computed from a statistical model including the distribution of the known-matching (KM or within) and known-nonmatching (KNM or between) comparison scores. Current LR procedures rely on KM/KNM scores from existing reference firearm toolmark data sets or alternatively from generating a set of test fires using multiple firearms. Both procedures may contain theoretical or practical issues which may hinder the LR procedures from reporting an unbiased LR estimation in casework. In this paper, a reference data set was established from a set of firearms, each test-fired two cartridge cases, resulting in a basic data set and a control data set. The congruent matching cells (CMC) method was used to generate CMC scores that are used to fit in the KM/KNM statistical distributions for LR estimation. In the initial test, 130 firearms from eight manufacturers were used for generating a reference data set consisting of 260 cartridge cases representing 130 KM and 8385 KNM pairwise breech face images. Test results showed that the KM and KNM distribution intersect at CMC = 2, which is equivalent to LR = 1 (equally to support both the prosecutor and the defense propositions). When the CMC threshold is increased to 6 or more, the LR values are higher than a million, which can provide extremely strong support to the conclusion of the same firearm (or the prosecutor's proposition) in the casework of firearm evidence identification.     

Understanding research methods,limitations, and applications of drug data collected by the National Forensic Laboratory Information System (NFLIS-Drug)

The National Forensic Laboratory Information System (NFLIS) is a drug surveillance program of the US Drug Enforcement Administration that systematically collects data on drugs that are seized by law enforcement and submitted to and analyzed by the Nation's forensic laboratories (NFLIS-Drug). NFLIS-Drug data are increasingly used in predictive modeling and drug surveillance to examine drug availability patterns. Given the complexity of the data and data collection, there are some common methodological pitfalls that we highlight with the aim of helping researchers avoid these concerns. The analysis done for this Technical Note is based on a review of the scientific literature that includes 428 unique, refereed article citations in 182 distinct journals published between January 1, 2005, and April 30, 2021. Each article was analyzed according to how NFLIS-Drug data were mentioned and whether NFLIS-Drug data were included. A sample of 37 articles was studied in-depth, and data issues were summarized. Using examples from the literature, this Technical Note highlights eight broad concerns that have important implications for the proper applications, interpretations, and limitations of NFLIS-Drug data with suggestions for improving research methods and accurate reporting of forensic drug data. NFLIS-Drug data are timely and provide key information to inform drug use trends across the United States; however, our present analysis shows that NFLIS-Drug data are misunderstood and represented in the literature. In addition to highlighting these issues, DEA has created several resources to assist NFLIS data users and researchers, which are summarized in the discussion.     

Interpreting perimortem blast trauma from skeletal remains: Complications and considerations

Blast trauma results from highly variable events that can lead to similar effects in the skeleton. Clinical literature, which largely focuses on soft tissue, provides limited efficacy for interpreting fully skeletonized cases. Interpretation of skeletal blast trauma is hampered by the low number of fully skeletonized case studies and experimental replication studies, which mainly use nonhuman proxies. The purpose of this study is to discuss fracture patterns on two individuals from WWII as a means to better understand and identify fracture patterns associated with blast trauma. Existing clinical and anthropological criteria are reviewed and applied to two World War II cases, both presumed to exhibit blast trauma based on historical contexts. These case studies exhibit combinations of complicated and extensive signs of blunt-force and projectile trauma, reflecting the diversity of skeletal trauma resulting from blast-related events. This analysis emphasizes the arguably impossible task of establishing a diagnosis based on the available literature and lack of prior knowledge about specific losses. Ultimately, analysts must consider the totality of skeletal trauma, combining biomechanical theory and relevant clinical and anthropological literature to arrive at useful yet defensible assessments of trauma. However, refined criteria and additional studies are needed to assess complicated trauma from blast-related events in anthropological contexts.     

Identifying reliable ions for the statistical differentiation of structurally similar fentanyl analogs

Definitive identification of fentanyl analogs based on mass spectral comparison is challenging given the high degree of structural and, hence, spectral similarity. To address this, a statistical method was previously developed in which two electron-ionization (EI) mass spectra are compared using the unequal variance t-test. Normalized intensities of corresponding ions are compared, testing the null hypothesis (H₀) that the difference in intensity is equal to zero. If H₀ is accepted at all m/z values, the two spectra are statistically equivalent at the specified confidence level. If H₀ is not accepted at any m/z value, then there is a significant difference in intensity at that m/z value between the two spectra. In this work, the statistical comparison method is applied to distinguish EI spectra of valeryl fentanyl, isovaleryl fentanyl, and pivaloyl fentanyl. Spectra of the three analogs were collected over a 9-month period and at different concentrations. At the 99.9% confidence level, the spectra of corresponding isomers were statistically associated. Spectra of different isomers were statistically distinct, and ions responsible for discrimination were identified in each comparison. To account for inherent instrument variations, discriminating ions for each pairwise comparison were ranked based on the magnitude of the calculated t-statistic (t_calc) value. For a given comparison, ions with higher t_calc values are those with the greatest difference in intensity between the two spectra and, therefore, are considered more reliable for discrimination. Using these methods, objective discrimination among the spectra was achieved and ions considered most reliable for discrimination of these isomers were identified.     

In search of identity: The field of forensic anthropology in Brazil—Profession and practice

The existing divergencies in the development of forensic anthropology (FA) around the world justify an analysis of its situation in each country/region. Our objective is to report information gathered directly from professionals acting in the field of forensic anthropology in Brazil, with the aim of highlighting the challenges of the discipline and contributing to its advancement. The research consisted of personal visits in Medico‐Legal Institutes (IMLs) in nine states of the country and semi‐structured interviews with 16 professionals. Detailed analysis of the Results suggests the field of forensic anthropology, despite the engagement and dedication of its professionals, cannot yet be considered a well‐structured discipline across the country. The academic background of professionals is highly heterogenous. The applied methods vary, and common protocol is not always followed. The demand highly exceeds the available human resources. The lack of comparative material Results in high percentage of cases remaining unsolved. Important divergences exist in terms of infrastructure and professional resources between the states. The limited cooperation between different IMLs and between different sections of the same IML—together with a general disbelief in the usefulness of anthropological examination in forensic cases—hampers FA’s development. There is a great openness for scientific collaboration and an abundance of material for research. Our research demonstrated structural, political, and academic limitations that affect the FA field in Brazil. However, the expertise and dedication of professionals point to human potential as the chief strength of this discipline that supports and enables research, providing high‐quality services in a challenging context.     

Can computed tomography replace or supplement autopsy?

Postmortem computed tomography (PMCT) has been integrated into the practice of many forensic pathologists. To evaluate the utility of PMCT in supplementing and/or supplanting medicolegal autopsy, we conducted a prospective double-blind comparison of abnormal findings reported by the autopsy pathologist with those reported by a radiologist reviewing the PMCT. We reviewed 890 cases: 167 with blunt force injury (BFI), 63 with pediatric trauma (under 5 years), 203 firearm injuries, and 457 drug poisoning deaths. Autopsy and radiology reports were coded using the Abbreviated Injury Scale and abnormal findings and cause of death (COD) were compared for congruence in consensus conferences with novel pathologists and radiologists. Overall sensitivity for recognizing abnormal findings was 71% for PMCT and 74.6% for autopsy. Sensitivities for PMCT/autopsy were 74%/73.1% for BFI, 61.5%/71.4% for pediatric trauma, 84.9%/83.7% for firearm injuries, and 56.5%/66.4% for drug poisoning deaths. COD assigned by reviewing PMCT/autopsy was correct in 88%/95.8% of BFI cases, 99%/99.5% of firearm fatalities, 82.5%/98.5% of pediatric trauma deaths, and 84%/100% of drug poisoning deaths of individuals younger than 50. Both autopsy and PMCT were imperfect in recognizing injuries. However, both methods identified the most important findings and are sufficient to establish COD in cases of BFI, pediatric trauma, firearm injuries and drug poisoning in individuals younger than 50. Ideally, all forensic pathologists would have access to a CT scanner and a consulting radiologist. This would allow a flexible approach that meets the diagnostic needs of each case and best serves decedents' families and other stakeholders.