Assessing the background levels of body fluids on hands

Forensic scientists are often asked to assist the court by evaluating the significance of finding body fluids on the hands of an individual; however, there is an absence of published data regarding the background levels of body fluids on hands. Whilst the scientist can use casework experience to inform the courts on the significance of the results, it would be advantageous to have data which could assist with this interpretation. This study was designed to ascertain the background levels of blood, semen, saliva, hairs/fibres and staining/debris on hands in the general population by sampling from delegates attending a scientific conference.The findings suggest that approximately one third of the population would be expected to have hairs or fibres on their hands and that females are more likely to have visible staining on their hands than males. Presumptive tests for blood and semen yielded negative results in all samples; however, almost 2 % of the samples were found to contain a very low number of sperm heads. In contrast, the majority of samples tested positive for the presence of saliva using the presumptive Phadebas® amylase test. The data supports the caution applied by forensic practitioners when evaluating the presence of saliva detected using the presumptive Phadebas® amylase test based on the lack of specificity and indicates that the RSID™-Saliva test would be more suitable to use.     

Preparation of a low-cost fingerprint powder that harnesses white light to emit long-lived phosphorescence

An inexpensive, commercially available doped strontium aluminate phosphor with long-lived afterglow has been prepared and assessed in the role of a luminescent fingerprint dusting powder. Blue, green, and aqua phosphorescence persisting for ca. 30 s was obtainable from treated fingermarks after charging the powders with the white light (400–700 nm) setting of a forensic light source. Imaging the phosphorescent afterglow enabled the elimination of background emissions encountered during latent fingermark examination. This was demonstrated by visualising fingermarks on substrates that possess inbuilt fluorescent security features and highly patterned substrate backgrounds, without any need for bespoke scientific equipment.     

Retrospective analysis of factors affecting rate of skeletonization within a tropical climate

Estimating the post mortem interval (PMI) in skeletonized cases is an extremely challenging exercise. Sri Lanka lacks adequate taphonomic research which is a serious limitation when assessing PMI in forensic death investigations. Methods that have been proposed to estimate PMI using the total body score (TBS) and accumulated degree days (ADD) are mainly based on data from continental and temperate climates and have shown less reliability in tropical climates. With the intention of developing a region-specific, evidence-based guide which would be applicable to tropical climates like Sri Lanka, we selected thirteen skeletonized remains with known PMIs from forensic case records and analysed their taphonomy in relation to selected weather data. We also compared the ADD values within our dataset with reference ranges calculated using published formula.All except one were found from outdoor locations. The TBS ranged from 24 to 32 and had a weak positive correlation with the PMI. The earliest appearance of skeletonization was 15 days in a body found indoors. The highest rate of skeletonization was seen in a body with a TBS of 32 and a PMI of 23 days. The average daily temperature and relative humidity were similar across all the cases however, the amount of rainfall varied. Bodies exposed to monsoon rains (n = 6) had a lower mean rate of skeletonization compared to those that were not exposed (n = 4) suggesting lower rates of decomposition during periods of heavy rainfall.No correlation was found between ADD and TBS. In 9 (69.2%) cases, the actual ADD was much lower than reference ADD ranges for TBS values, indicating poor applicability of TBS and ADD based formulae in estimating PMI within the Sri Lankan climate. Our study shows a strong need for taphonomic and entomological research in tropical climates to further explore the impact of monsoons on biotic and abiotic factors affecting skeletonization.     

The effects of four different solvent vapours on the restoration of obliterated stamp markings from five different wooden surfaces

The stamp markings on wooden surfaces, which are placed on trees and products including antiques, indicate the status of trees and involve identifying data regarding the products. Such markings are obliterated either to facilitate illegal logging or to conceal product information. Despite the wide literature on the restoration of obliterated characters on metal and polymer surfaces, the recovery of defaced characters on wooden surfaces appears to be understudied. Several reference texts in the forensic marks’ examination literature suggest that water, water vapor, and alkaline solutions are useful in restoring the abraded markings on the wood. Since there does not seem to be any experimental study proving such success, this study aimed to fill this gap. This study conducted experimental research by using water, ethanol, ammonia, and chloroform to recover the scraped characters on samples obtained from walnut, beech, spruce, oak, and cedar trees. The cold-stamped characters, which were defaced at varying depths, were restored using vapor and liquid phases of four solvents. While the vapor phases of water, ethanol, and ammonia yielded good outcomes on all types of wooden surfaces, the liquid phases did not seem to be useful in the revisualization process. The response of the vapors, which varied between 62 and 220 s, depended on the type of wood. The restoration technique developed in this research offers the possibility of on-site usage, easy application, utilization of low-cost solvents, rapid recovery, and effectiveness on various wooden surfaces. Overall, the restoration methodology used in this research appears to be fruitful in retrieving identifying information on wooden samples.     

Lipidic compounds found in soils surrounding human decomposing bodies and its use in forensic investigations – A narrative review

Following decomposition of a human body, a variety of decomposition products, such as lipids, are released into the surrounding environment, e.g. soils. The long-lasting preservation in soils and their high diagnostic potential have been neglected in forensic research. Furthermore, little is known about the preservation, chemical transformation, or degradation of those human derived lipids in soils. To date, several studies identified various lipids such as long-chain free fatty acids and steroids in soils that contained decomposition fluids. Those lipids are preserved in soils over time and could serve as markers of human decomposition in forensic investigations, e.g. for estimating the post-mortem interval or identifying the burial location of a human body. Therefore, this review focuses on the current literature regarding fatty acid and steroid that have been detected in soils and associated with human body decomposition. After a short introduction about human decomposition processes, this review summarises fatty acid and steroid analysis applied in current case studies and studies related to taphonomic research. This review provides an overview of the available studies that have used fatty acids and steroids as identifiers of human decomposition fluid in soils in a forensic context and discusses the potential for developing this innovative field of research with direct application in a forensic context.     

Extended reality (XR) virtual practical and educational eGaming to provide effective immersive environments for learning and teaching in forensic science

Online virtual learning resources have been available for learning and teaching in forensic science for some years now, but the recent global COVID-19 related periods of irregular lockdown have necessitated the rapid development of these for teaching, learning and CPD activities. However, these resources do need to be carefully constructed and grounded in pedagogic theory to be effective. This article details eXtended Reality (XR) learning and teaching environments to facilitate effective online teaching and learning for forensic geoscientists. The first two case studies discussed in this article make use of Thinglink software to produce virtual learning and teaching XR resources through an internet system, which was delivered to undergraduate students in 2021. Case one details a range of XR virtual laboratory-based equipment resources, providing a consistent, reliable and asynchronous learning and teaching experience, whilst the second case study presents an XR virtual learning applied geophysics resource developed for a 12-week CPD training programme. This programme involves recorded equipment video resources, accompanying datasets and worksheets for users to work through. Both case studies were positively received by learners, but there were issues encountered by learners with poor internet connections or computer skills, or who do not engage well with online learning. A third case study showcases an XR educational forensic geoscience eGame that was developed to take the user through a cold case search investigation, from desktop study through to field reconnaissance and multi-staged site investigations. Pedagogic research was undertaken with user questionnaires and interviews, providing evidence that the eGame was an effective learning and teaching tool. eGame users highly rated the eGame and reported that they raised awareness and understanding of the use of geophysics equipment and best practice of forensic geoscience search phased investigations. These types of XR virtual learning digital resources, whilst costly to produce in terms of development time and staff resource, provide a complementary virtual learning experience to in-situ practical sessions, and allow learners to asynchronously familiarise themselves with equipment, environments and techniques resulting in more efficient use of in situ time. The XR resources also allow learners to reinforce learning post in-situ sessions. Finally, XR resources can provide a more inclusive and authentic experience for learners who cannot attend or complete work synchronously.     

Background levels of body fluids and DNA on the shaft of the penis and associated underpants in the absence of sexual activity

This study examines the background of blood, saliva, semen and autosomal DNA on penile swabs and underpants from males in the absence of recent sexual activity. Based on the data collected by the AFSP Body Fluid Forum, the results of this study show that; there is a very low expectation of detecting blood on penile swabs and male underpants; a low expectation of detecting saliva on penile swabs and male underpants; and spermatozoa would be expected in less than a quarter of penile swabs and three quarters of male underpants. As none of the samples had detectable levels of DNA which were suitable for meaningful comparison that did not match the donor or their partner, the expectation of detecting a DNA profile from the cellular background on penile swabs or underpants from a male who has not been involved in recent sexual intercourse is very low. The results of this study are extremely informative when evaluating the significance of blood, saliva, semen and DNA detected on the penile swabs and underpants of males in cases of alleged sexual assault.     

Finding the missing and unknown: Novel educational approaches to warming up cold cases

In recent years, students in police academies and higher education institutions around the world have worked together to analyse cold cases including long-term missing persons cases in collaboration with investigators and prosecutors. In 2020, three European organisations, the Police Expert Network on Missing Persons (PEN-MP), AMBER Alert Europe and Locate International, succeeded in connecting these educational organisations enabling them to work collectively on cases and conduct cold case analyses (CCA) across international borders. The International Cold Case Analysis Project (ICCAP) learning objectives were to 1) collect the necessary information about the victim, 2) reconstruct the crime, and 3) investigate trace control.In a learning objective-based evaluation using Computer-Assisted Web Interviewing, 76 participating students from the German and International ICCAP teams were asked to complete a pre- and post-review questionnaire to self-assess their personal competence development. Participants reported significant increases in competence in all evaluated areas, thus demonstrating that authentic and relevant collaborations can enrich the learning environment, promote the use of professional skills, and provide significant knowledge exchange opportunities between academia and industry.Drawing on case studies of cold case missing persons' investigations and unidentified found remains, this article shares how university academics, students and community volunteers can work together nationally and internationally to find out what has happened to missing people and how we can more effectively identify the previously unidentified. In so doing, we share the expertise required to progress these cold cases and provide recommendations to support other institutions and organisations in adopting this innovative approach.     

Sentencing data-driven cybercrime. How data crime with cascading effects is tackled by UK courts

This paper contributes to research seeking to understand if and how legislation can effectively counter cybercrimes that compromise personal data. These ‘data crimes’, which are the ‘dark side’ of big data and the data economy enabled by cloud computing, display cascading effects, in that they empower disparate criminals to commit further crimes and victimise a broad range of individuals or data subjects. The paper addresses the under-researched area of sentencing, which, as the last step of the judicial process, plays a crucial role in how the law is interpreted and implemented.This paper investigates courts’ approach to the evolving technological environment of cybercrime captured by data crime and the cascade effect and whether the cascade effect can assist courts in dealing with data-driven cybercrime. The paper examines original data collected from UK courts, namely 17 sentencing remarks relating to cybercrime court cases decided in England & Wales between 2012 and 2019. The analysis shows that courts appreciate the impact of data crime and their cascading effects, but that the complexity of the offences is lost at sentencing, arguably due to the negative impact of systemic factors, such as technology neutral law and the lack of legal authorities.After examining such systemic factors, the paper suggests how the cascade effect could aid sentencing by adding specificity and context to data crime. The paper ends with avenues for further research relating to debates on fair cybercrime sentencing and open justice.     

Portion size matters: Carrion ecology lessons for medicolegal death investigations—A study in Cape Town,South Africa

Forensic taphonomic studies are regionally specific and improve time since death estimates for medico-legal casework. Within forensic taphonomy and carrion ecology, vertebrate scavengers are under-researched with many studies conducted using multiple, unclothed carcasses. This is a forensically unrealistic experimental design choice with unknown impact. The effect of variation in carrion biomass on the decomposition ecosystem, particularly where vertebrate scavengers are concerned, requires clarification. To assess the effect of carrion biomass load on vertebrate scavenging and decomposition rate, seasonal baseline data for single, clothed ~60 kg porcine carcasses were compared to clothed multiple-carcass deployments, in a forensically relevant habitat of Cape Town, South Africa. Decomposition was tracked via weight loss and bloat progression and scavenging activity via motion-activated cameras. The single carcasses decayed more quickly, particularly during the cooler, wetter winter, strongly correlated with concentrated Cape gray mongoose (Galerella pulverulenta) scavenging activity. On average and across seasons, the single carcasses lost 68% of their mass by day 32 (567 accumulated degree days [ADD]), compared to 80 days (1477 ADD) for multi-carcass deployments. The single carcasses experienced substantially more scavenging activity, with longer visits by single and multiple mongooses, totaling 53 h on average compared to 20 h for the multi-carcass deployments. These differences in scavenging activity and decay rate demonstrate the impact of carrion biomass load on decomposition for forensic taphonomy research. These findings need corroboration. However, forensic realism requires consideration in taphonomic study design. Longitudinally examining many single carcasses may produce more forensically accurate, locally appropriate, and usable results.     

Post-mortem interval estimation using miRNAs of road traffic accident cases: A forensic molecular approach

In forensic examination accurate estimation of post-mortem interval (PMI) is a challenging task, particularly in the advanced stages of decomposition. The existing methods (algor mortis, livor mortis, rigor mortis, putrefaction etc) used for estimating PMI rely on analyzing the physical, biochemical, and metabolic changes that occur in the corpse after death. While these methods have shown some level of effectiveness in estimating PMI during the early stages of decomposition, accurate estimation becomes increasingly challenging during the later stages of putrefaction when the body undergoes significant changes. Recently, microRNA (miRNA) profiling due to its relatively small size and stability has emerged as a promising tool in several areas of forensics. This study demonstrates the potential of miRNA for PMI estimation in advanced stages of death. In this study, miRNA-195, miRNA-206, and miRNA-378 were selected as target miRNAs and miRNA-1 as reference miRNA. Left ventricle tissue (5 g) of the heart from 20 forensic autopsies of traffic accident victims (18–32 years) were collected and processed. The samples were held at room temperature for eight different time intervals (12, 24, 48, 72, 96, 120, 168 and 196 h), and RNA was extracted from all the samples using Trizol-based RNA isolation protocol, followed by cDNA synthesis and amplification with commercially available specific miRNA probes in Real-Time PCR (RT-PCR), Ct was calculated. The result showed that miRNAs were associated with PMI. Over time, there were substantial changes in the Ct values of all three miRNAs, with significant reductions observed at 196 h compared to 12 h. miRNA-206 demonstrated significant changes at multiple time intervals, while miRNA-1 remained stable for up to 196 h and thus holds caas an endogenous marker. In conclusion, miRNA has the potential to serve as a valuable tool for estimating PMI, especially during the advanced stages of decomposition, when used in conjunction with established techniques. However, further validation of the study is required to obtain more accurate estimates of PMI.     

A retrospective comparative study to evaluate the reliability of post-mortem interval sources in UK and US medico-legal death investigations

Post-mortem interval (PMI) information sources may be subject to varying degrees of reliability that could impact the level of confidence associated with PMI estimations in forensic taphonomy research and in the practice of medico-legal death investigation. This study aimed to assess the reliability of PMI information sources in a retrospective comparative analysis of 1813 cases of decomposition from the Allegheny County Office of the Medical Examiner in Pittsburgh, US (n = 1714), and the Crime Scene Investigation department at Southwest Forensics in the UK (n = 99). PMI information sources were subjected to a two-stage evaluation using an adapted version of the 3x5 aspects of the UK police National Intelligence Model (NIM) to determine the confidence level associated with each source. Normal distribution plots were created to show the distribution frequency of the dependent variables (decomposition stage and source evaluation) by the independent variable of PMI. The manner, location, and season of death were recorded to ascertain if these variables influenced the reliability of the PMI. A confidence matrix was then created to assess the overall reliability and provenance of each PMI information source. Reliable PMI sources (including forensic specialists, missing persons reports, and digital evidence) were used across extensive PMI ranges (1 to 2920 days in the US, and 1 to 240 days in the UK) but conferred a low incidence of use with forensic specialists providing a PMI estimation in only 35% of all homicide cases. Medium confidence PMI sources (e.g., last known social contact) accounted for the majority of UK (54%, n = 54) and US (82%, n = 1413) cases and were associated with shorter PMIs and natural causes of death. Low confidence PMI sources represented the lowest frequencies of UK and US cases and exclusively comprised PMI information from scene evidence. In 96% of all cases, only one PMI source was reported, meaning PMI source corroboration was overall very low (4%). This research has important application for studies using police reports of PMI information to validate PMI estimation models, and in the practice of medico-legal death investigation where it is recommended that i) the identified reliable PMI sources are sought ii) untested or unreliable PMI sources are substantiated with corroborating PMI information, iii) all PMI sources are reported with an associated degree of confidence that encapsulates the uncertainty of the originating source.     

A Forensic Entomological Analysis Can Yield an Estimate of Postmortem Interval,and Not Just a Minimum Postmortem Interval: An Explanation and Illustration Using a Case

Several authors claimed that a forensic entomological analysis can never be interpreted as the postmortem interval (PMI), but that it can be interpreted as a minimum postmortem interval (PMI_min), or dead for not less than X amount of time. Because in most instances, a PMI estimate should be a range, that is, the set of values from maximum postmortem interval (PMI_max) to PMI_min, objections to PMI estimation are objections to PMI_max estimation. The arguments for this position did not address the substantial body of literature describing estimation of both PMI_max and PMI_min using insect succession analysis. This report reviews the scientific issues and presents a recent homicide investigation in which several forensic entomology experts used the absence of carrion insects on the corpse, a kind of succession analysis, to estimate PMI or PMI_max.     

脑组织与其相关分析推断死亡时间的研究进展

推断死后间隔时间(postmortem interval,PMI)一直是法医学鉴定中需要解决的重要问题之一.可用于推断PMI的尸体检材有很多种,脑组织因其独特的解剖学位置与生理功能,是推断PMI的重要检材之一.本文从三个方面将根据脑组织推断PMI的方法进行综述,包括了通过脑组织的温度、形态特点等尸体现象推断PMI;通过...     

Dehydration-Induced alterations to sharp force trauma on Sus domesticus radii

Dehydration is a taphonomic process that affects nearly all skeletal remains, yet there is a dearth of evidence on this process within the forensic taphonomy literature. When considering the forensic implications of skeletal dehydration, a particular area of concern is sharp force trauma due to its global prominence in forensic cases. In an attempt to address these literature gaps and quantify the effects that dehydration has on skeletal elements, a controlled experiment subjected Sus domesticus (i.e., domestic pig) radii samples (n = 36) to laboratory-induced dehydration after they were inflicted with knife trauma. All samples were photographed pre- and post-dehydration; bone section and kerf mark length, width, and area were then measured from these photographs using ImageJ. Statistical analysis of pre- and post-dehydration samples showed that all measurements experienced significant (p ≤ 0.001) shrinkage, with bone sample area shrinking an average of 8.8 % and kerf mark area an average of 29.7 %. Alterations in length, width and area between the kerf marks and bone samples showed a weak, moderate, and strong correlation, respectively. These findings suggest that anthropological analysis may be affected by dehydration-induced shrinkage, highlighting the necessity of continued research into the effects of dehydration on skeletal trauma.     

Pressing need for national governmental recognition of forensic anthropology in South Africa as illustrated in a medico-legal case

Forensic anthropology in South Africa is well developed in the higher education sector, with advanced training and research programmes. Despite this and decades of academic involvement in casework, forensic anthropology still lacks a defined framework and mandate at a governmental level. Therefore, the involvement of forensic anthropologists’ expertise varies markedly between cases, provinces, and among various stakeholders within the country, to the detriment of dispensation of social and criminal justice. The lack of clearly defined guidelines for the rendering of the service was exemplified and demonstrated through a recent forensic case. Here, contextual information was absent, and the remains posed a challenge to analyse, ostensibly due to missing information. Numerous questions were raised during the analysis of the remains, and broader concerns about the investigative involvement of a forensic anthropologist within South African casework were brought to the fore. Through the analysis of this case, we describe the deductive processes that led to the formation of an opinion that the skeletal linear defects were the result of taphonomic changes. In addition, we highlight how these efforts where constrained and each step in the process unnecessarily hindered. Finally, we demonstrate the capacity and willingness of forensic anthropology practitioners to be involved, and how, without governmental support, it is a great potential lamentably untapped.     

Corneal‐Smart Phone: A novel method to intelligently estimate postmortem interval

The changes of postmortem corneal opacity are often used to roughly estimate the postmortem interval (PMI) in forensic practice. The difficulty associated with this time estimate is the lack of objective means to rapidly quantify postmortem corneal changes in crime scenes. This study constructed a data analysis model of PMI estimation and implemented an intelligent analysis system for examining the sequential changes of postmortem corneal digital images, named Corneal‐Smart Phone, which can be used to quickly estimate PMI. The smart phone was used in combination with an attachment device that provided a darkroom environment and a steady light source to capture postmortem corneal images. By segmenting the corneal pupil region images, six color features, Red (R), Green (G), Blue (B), Hue (H), Saturation (S), Brightness (V) and four texture features Contrast (CON), Correlation (COR), Angular Second Moment (ASM), and Homogeneity (HOM), were extracted and correlated with PMI model. The results indicated that CON had the highest correlation with PMI (R² = 0.983). No intra/intersubject variation in CON values were observed (p > 0.05). With the increase in ambient temperature or the decrease in humidity, the CON values were increased. PMI prediction error was <3 h within 36 h postmortem and extended to about 6–8 h after 36 h postmortem. The correct classification rate of the blind test samples was 82%. Our study provides a method that combines postmortem corneal image acquisition and digital image analysis to enable users to quickly obtain PMI estimation.     

Citrate Content of Bone as a Measure of Postmortem Interval: An External Validation Study

The postmortem interval (PMI) of skeletal remains is a crucial piece of information that can help establish the time dimension in criminal cases. Unfortunately, the accurate and reliable determination of PMI from bone continues to evade forensic investigators despite concerted efforts over the past decades to develop suitable qualitative and quantitative methods. A relatively new PMI method based on the analysis of citrate content of bone was developed by Schwarcz et al. The main objective of our research was to determine whether this work could be externally validated. Thirty‐one bone samples were obtained from the Forensic Anthropology Center, University of Tennessee, Knoxville, and the Onondaga County Medical Examiner's Office. Results from analyzing samples with PMI greater than 2 years suggest that the hypothetical relationship between the citrate content of bone and PMI is much weaker than reported. It was also observed that the average absolute error between the PMI value estimated using the equation proposed by Schwarcz et al. and the actual (“true”) PMI of the sample was negative indicating an underestimation in PMI. These findings are identical to those reported by Kanz et al. Despite these results this method may still serve as a technique to sort ancient from more recent skeletal cases, after further, similar validation studies have been conducted.     

Blood and sperm traces on human hair. A study on preservation and detection after 3-month outdoor exposure

Hair can retain important biological traces for forensic investigations. Forensic scientists are used to looking for such traces on clothing and skin of victims, however, when decomposition kicks in and all that remains of the victims is the skeleton, hair may be the only tissue representing the surface of the body at the time of a crime on which biological traces of an aggressor may have been left and still be detectable. Given the lack of research on this topic, this pilot study aims to assess the capacity of hair to retain semen and blood in hair, and the possibility to detect these fluids with well-known techniques and to obtain a useful genetic profile even when exposed to environmental conditions (Open Natural Environment (woods), Open Man Made Environment (urban)) for three months.Results showed that both traces were always visible and detectable with almost all techniques in the Control Environment, while in the two open environments some difficulties arose. However, biomolecular analysis was effective up to three months on both fluids in the Natural Environment and up to two months and one week respectively on blood and semen in the Man Made Environment. The Combur Test, OBTI, and Luminol were effective on blood up to three months in both environments while Sperm-HY-Liter and observation of cellular components were effective on semen up to at least 1 month and PSA testing was positive up to 1 week in both environments.The present work can be considered an encouraging starting point for the analysis of biological traces on hair in forensic contexts, regardless of the PMI, since blood and semen related to a crime may survive.