Comparison of DNA recovery methods and locations from regularly-worn hooded jumpers before and after use by a second wearer.

Items of worn clothing are routinely examined for DNA in forensic casework, commonly with the expectation that at least some of the DNA will come from a wearer of the item, so-called 'wearer DNA'. This study investigated DNA recovered from hooded jumpers that were regularly worn and laundered for four weeks and then subsequently worn by a different individual for four hours. This study also systematically investigated whether using different recovery methods or sampling locations on the jumpers might distinguish between DNA deposited by the regular and most recent wearers of clothing. Four volunteers each wore a new hooded jumper regularly (6 h/day, 2 days/week, washed at weekends) during two 4-week periods. At the end of each month, DNA was first recovered by cutting out and mini-taping the inside left cuff, half-collar, pocket and underarm fabric. The jumpers were then worn by a different individual for four hours, and DNA was again recovered by cutting out and mini-taping, but this time from the inside right cuff, half-collar, pocket and underarm fabric. All DNA samples (n = 128) were quantified and profiled. DNA quantities ranged from 0 to âˆ¼40 ng with an outlier of âˆ¼150 ng, and no significant differences were observed among recovery methods and sampling locations, nor whether one or two wearers had worn the jumpers. However, one volunteer consistently deposited significantly more DNA to their jumpers than two other volunteers, confirming the impact of 'shedder status' on DNA deposition during wearing of clothing. When jumpers were regularly worn by one wearer, the majority (72.7-83.3 %) of the samples for all wearers across both months comprised a major profile of the wearer with a minor profile of non-wearer alleles. When jumpers were then worn by a second wearer, the composition of the profiles obtained were generally reproducible across the recovery methods used, the sampling locations and the two replicates of the experiment for each pairing of wearers. However, profile compositions differed between wearer pairings. Overall, ∼60 % of profiles obtained gave a major profile of the regular wearer, whereas âˆ¼30 % gave a major profile of the second wearer. The remaining profiles comprised other much less frequent observations of single-source profiles of each wearer and equal proportions of DNA from both wearers. Non-wearer DNA was also observed in the majority of samples, both before and after jumpers were worn by a second wearer. For one volunteer's jumpers, a recurring non-wearer DNA profile was observed that could be attributed to their romantic partner, and this DNA persisted on the jumpers even after being worn by the second wearer. This study provides insight on the impact of shedder status, multiple wearers, different recovery methods and sampling locations on the quantities of DNA and compositions of DNA profiles recovered from authentically regularly-worn hooded jumpers. The findings also provide a preliminary dataset that can be used to infer activity level probabilities in casework.

Human identification: an investigation of 3D models of paranasal sinuses to establish a biological profile on a modern UK population.

Medical imaging is a valuable source for facilitating empirical research and provides an accessible gateway for developing novel forensic anthropological methods for analysis including 3D modelling. This is especially critical for the United Kingdom (UK), where methods developed from modern UK populations do not currently exist. This study introduces a new approach to assist in human identification using 3D models of the paranasal sinuses. The models were produced from a database of 500 modern CT scans provided by University College London Hospital. Linear measurements and elliptic Fourier coefficients taken from 1500 three-dimensional models across six ethnic groups assessed by one-way ANOVA and discriminant function analysis showed a range of classification rates with certain rates reaching 75-85.7% (p < 0.05) in correctly classifying age and sex according to size and shape. The findings offer insights into the potential for employing paranasal sinuses as an attribute for establishing the identification of unknown human remains in future crime reconstructions.

Sex estimation from virtual models: exploring the potential of stereolithic 3D crania models for morphoscopic trait scoring.

Modern computed tomography (CT) databases are becoming an accepted resource for the practice and development of identification methods in forensic anthropology. However, the utility of 3D models created using free and open-source visualization software such as 3D Slicer has not yet been thoroughly assessed for morphoscopic biological profiling methods where virtual methods of analysis are becoming more common. This paper presents a study that builds on the initial findings from Robles et al. (2020) to determine the feasibility of estimating sex on stereolithic (STL) 3D cranial models produced from CT scans from a modern, living UK population (n = 80) using equation 2 from the Walker's (2008) morphoscopic method. Kendall's coefficients of concordance (KCC) indicated substantial agreement using cranial features scores in an inter-observer test and a video-inter-observer test. Fleiss' Kappa scores showed moderate agreement (0.50) overall between inter-observer sex estimations, and for observer sex estimations in comparison to recorded sexes (0.56). It was found that novice users could virtually employ morphoscopic sex estimation methods effectively on STL 3D cranial models from modern individuals. This study also highlights the potential that digital databases of modern living populations can offer forensic anthropology. Key points: First example of Walker's (2008) method applied to a living UK population.Open-source software is a valuable resource for crime reconstruction approaches.Male scoring bias was observed in method application.Forensic anthropologists would benefit from virtual anthropology training to use and interpret 3D models.Digital databases offer more ethical, diverse, modern populations for future research.

Drilling down into ethics: A thematic review of ethical considerations for the creation and use of 3D printed human remains in crime reconstruction.

The existing literature contains some exploration of the ethics concerning human remains in forensic and virtual anthropology. However, previous work has stopped short of interrogating the underlying ethical concepts. The question of how people understand and apply these concepts in practice, and what it means to act ethically, remain underexplored. This thematic review explores the ethical considerations that contribute to the creation and use of 3D printed human remains for forensic purposes. The three main branches of ethical theory are outlined to explore how they may apply to forensic practice. Key themes relating to 3D printing human remains in forensic contexts were explored to better understand the ethics landscape, ethical challenges, and the current guidelines in place. Through this thematic review, nine ethics principles were identified as key principles for guiding best practice: anonymity, autonomy, beneficence, consent, context, justice, non-maleficence, proportionality, and transparency. It is suggested that these principles could be incorporated into adaptable guidelines going forward to support ethical practice. The findings also suggest that holistic ethics cognition training may have value in supporting forensic scientists in ethical decision-making, together with procedural and structural design that may promote best practice and reduce cognitive load.

Regaining creativity in science: insights from conversation.

The 'early modern' (Renaissance) workshop was predicated on the idea that informal, open-ended cooperation enables participants to experience difference and develop new insights, which can lead to new ways of thinking and doing. This paper presents the insights that emerged from a conversation event that brought wide-ranging voices together from different domains in science, and across the arts and industry, to consider science leadership as we look to the future in a time of interlocking crises. The core theme identified was a need to regain creativity in science; in the methods of scientific endeavours, in the way science is produced and communicated, and in how science is experienced in society. Three key challenges for re-establishing a culture of creativity in science emerged: (i) how scientists communicate what science is and what it is for, (ii) what scientists value, and (iii) how scientists create and co-create science with and for society. Furthermore, the value of open-ended and ongoing conversation between different perspectives as a means of achieving this culture was identified and demonstrated.

A method to induce stress in human subjects in online research environments.

This paper presents a method to induce stress in human subjects during online participation in research studies without the presence of researchers. In this study, participants in the stress-inducing condition (N = 52, 44%) were asked to answer general knowledge and mathematical questions which people often get wrong, and did so under time pressure as well as receiving feedback. In contrast, participants in the control condition (N = 66, 56%) did not have time pressure or receive feedback. The stress manipulation was found to be effective, as the reported state anxiety and visual analog scale on stress scores were higher for the stress group than for the non-stress group (both findings, p < 0.001). Consistent findings were found when accounting for trait anxiety as a moderator, with the exception of the state anxiety levels in high trait anxiety group. This stressing method combines the established stress conditions of uncontrollability (such as time pressures) and social evaluative threats (such as negative feedback). In addition, the method contains specific measures (such as a commitment statement and attention check questions) to enhance the internal validity by preventing and detecting cheating or random responses. This method can be deployed through any commonly available online software. It offers a simple and cost-effective way to collect data online - which fits the increasing need to carry out research in virtual and online environments.

Investigating the uses of mobile phone evidence in China criminal proceedings.

Data from mobile phones are regularly used in the investigation of crime and court proceedings. Previously published research has primarily addressed technical issues or provided operational manuals for using forensic science evidence, rather than analysing human factors and the implementation of forensic tools in investigation settings. Moreover, previous research has focused almost entirely on western countries, and there is a dearth of research into the uses of forensic evidence in China. In this study, a review was carried out of court sentencing documents referring to mobile phone evidence in China over the period 2013-2018. Automated content analysis was used to identify the specific evidence types utilised and the sentencing outcome for each case. Results show that mobile phone evidence was used in 3.3% of criminal proceedings. Among various data types mentioned in criminal proceedings, call records sustained as the most frequently used type of data. After which, instant messaging tools (e.g. WeChat) are an increasing proportion of all mobile phone evidence, from 1% in 2015 to 25% in 2018. For cases that utilised mobile phone data, the analysis of instant messaging and online transaction tools is routine, with little variation in the use of each application (WeChat, Alipay, QQ) for investigations of different types of crime. However, in the majority of criminal cases, mobile phone data function as subsidiary evidence and posed limited impacts on verdict reached. The current findings indicate that a large amount of mobile phone evidence was transformed into other evidence formats or filtered out directly before court proceedings.

A multi-method assessment of 3D printed micromorphological osteological features.

The evaluation of 3D printed osteological materials has highlighted the difficulties associated with accurately representing fine surface details on printed bones. Moreover, there is an increasing need for reconstructions to be demonstrably accurate and reliable for use in the criminal justice system. The aim of this study was to assess the surface quality of 3D prints (n = 9) that presented with micromorphological alterations from trauma, taphonomy and pathology processes. The archaeological bones were imaged using micro-CT scanning and 3D printed with selective laser sintering (SLS) printing. A multi-method experimental approach subsequently identified: (1) the 3D printed bones to be metrically accurate to within 1.0 mm; (2) good representation of micromorphological surface features overall, albeit with some loss of intricate details, depths, and fine textures that can be important for visual processing; (3) five of the nine 3D printed bones were quantitatively scored as accurate using the visual comparison method; and, (4) low mesh comparison distances (± 0.2 mm) between the original models and the digitised 3D print models. The findings offer empirical data that can be used to underpin 3D printed reconstructions of exhibits for use in courts of law. In addition, an adaptable pathway was presented that can be used to assess 3D print accuracy in future reconstructions.

3D forensic science: A new field integrating 3D imaging and 3D printing in crime reconstruction.

3D techniques are increasingly being used by forensic scientists in crime reconstruction. The proliferation of 3D techniques, such as 3D imaging and printing being employed across the various stages of the forensic science process, means that the use of 3D should be considered as a distinct field within forensic science. '3D Forensic Science' ('3DFS') is therefore presented in this paper as a field that brings together a range of 3D techniques and approaches that have been developed within different areas of forensic science for achieving crime reconstructions and interpreting and presenting evidence. It is argued that by establishing this distinct field, defining its boundaries, and developing expertise, best practice and standards, the contribution of 3DFS to the criminal justice system can be maximised and the accuracy and robustness of crime reconstruction endeavours can be enhanced.

Organizational and Human Factors Affecting Forensic Decision-Making: Workplace Stress and Feedback.

Although forensic examiners operate in a stressful environment, there is a lack of understanding about workplace stress and feedback. These organizational and human factors can potentially impact forensic science judgments. In this study, 150 practicing forensic examiners from one laboratory were surveyed about their experiences of workplace stress, and the explicit and implicit feedback they receive. Forensic examiners reported that their high stress levels originated more from workplace-related factors (management and/or supervision, backlogs, and the pressure to do many cases) than from personal related factors (family, medical, and/or financial). The findings showed that a few (8%) of the forensic examiners sometimes felt strong implicit feedback about what conclusions were expected from them and that some (14%) also strongly felt that they were more appreciated when they helped to solve a case (e.g., by reaching a "match" as opposed to an "inconclusive" conclusion). Differences were found when comparing workplace stress and feedback levels across three core forensic science fields (forensic biology, chemistry, and latent prints) and across career stages (early, mid, and late). Gaining insights into the stress factors within a workplace and explicit and implicit feedback has implications for developing policies to improve the well-being, motivation, and performance of forensic examiners.

Increasing the accessibility and impact of justice-related student and practitioner research.

Much good quality research by pre-doctoral students and case-work focused practitioners remains unpublished. However, their findings could contribute to the evidence base underpinning science and practice within international justice system contexts. There are two main challenges to making findings accessible: reaching all criminal justice stakeholders, and encouraging collaborative efforts in research addressing 'real world' problems. This article presents the rationale for a new, open access repository. The aim is to share good quality pre-doctoral and practitioner criminal justice research across traditional disciplinary and international borders. Such a repository should be easy to use, well maintained and sustainable. Its reach, value and impact also need to be measurable. We present the major considerations relating to the operation and workflow of such a repository, and outline the potential value, benefits and limitations. Our research suggests that the proposed repository could foster interdisciplinary and collaborative work to benefit global justice systems and societies.

The value of eye-tracking technology in the analysis and interpretations of skeletal remains: A pilot study.

This initial study is the first to use eye-trackers as a tool in order to study gaze pattern strategies and decision making processes involved in the assessment of skeletal remains. Three experienced participants were asked to wear eye-tracking glasses (Tobii Pro Glasses 2) when estimating sex and age-at-death of one set of skeletal remains from a known archeological sample. The study assessed participants' fixation points (the features of the skeleton focused on), fixation duration (the total time spent on each assessment and feature) as well as visit count and duration (the total number of visits and the duration of visits to particular areas). The preliminary results of this study identified differences in gaze "strategies" with regards to fixation points, visit duration, and visit counts between the participants. The data generated provide a starting point for assessing how such technologies could be used in order to more fully understand the decision making processes involved in forensic anthropological interpretations and their role in forensic reconstructions.

Persistence of transferred fragrance on fabrics for forensic reconstruction applications.

It has recently been established that volatile organic compounds (VOCs) successfully transfer between clothing even with a short contact of 10 s, highlighting the potential to use VOCs in forensic reconstruction scenarios, such as sexual assault cases. The mid and low volatility compounds transferred in greater amounts than high volatility compounds. This study presents empirical data addressing the persistence of transferred VOCs on clothing for the first time. A series of experiments were carried out to determine the persistence of VOCs on clothing for time periods of up 4 weeks, on natural and synthetic fibres, and at three different environmental temperatures. The data indicate that the highest VOC amounts are generally obtained for shorter persistence times of up to 1 d. Whilst high volatility compounds were not recovered in sufficient amounts to allow quantification, the four other transferred VOCs were successfully quantified for persistence times of up to 4 weeks. The persistence for mid-volatility compounds follows decay curve trends in line with those previously obtained for fibres, glass and pollen. When comparing the persistence of VOCs on a natural and a synthetic fibre, for a persistence time of 1 h, the transferred VOCs were retained on a natural fibre in higher amounts than on a synthetic fibre. However, for longer persistence times the concentration of VOCs was similar between the two fabrics. Lastly, lower environmental temperatures resulted in higher recoveries for most VOCs, especially for short persistence times. These findings demonstrate that optimal recovery of VOCs from clothing occurs when the fabric is kept at cooler temperatures and analysed soon after the fragrance transfer occurred, although VOC recovery was possible at higher temperatures and after longer persistence times. Given the transfer and persistence characteristics of VOCs from fragrance, there is potential for fragrance to be used as a form of trace in forensic reconstruction approaches.

A cultural change to enable improved decision-making in forensic science: A six phased approach.

There has been an increased engagement by researchers in understanding the decision-making processes that occur within forensic science. There is a rapidly growing evidence base underpinning our understanding of decision-making and human factors and this body of work is the foundation for achieving truly improved decision-making in forensic science. Such an endeavour is necessary to minimise the misinterpretation of scientific evidence and maximize the effectiveness of crime reconstruction approaches and their application within the criminal justice system. This paper proposes and outlines a novel six phased approach for how a broadening and deepening knowledge of decision-making in forensic science can be articulated and incorporated into the spheres of research, practice, education, and policy making within forensic science specifically, and the criminal justice system more generally. Phases 1 and 2 set out the importance of systematic examination of the decisions which play a role throughout forensic reconstruction and legal processes. Phase 3 focuses on how these decisions can, and should, be studied to understand the underlying mechanisms and contribute to reducing the occurrence of misleading decisions. Phase 4 highlights the ways in which the results and implications of this research should be communicated to the forensic community and wider criminal justice system. Lastly, the way in which the forensic science domain can move forwards in managing the challenges of human decision-making and create and embed a culture of acceptance and transparency in research, practice and education (learning and training) are presented in phases 5 and 6. A consideration of all 6 connected phases offers a pathway for a holistic approach to improving the transparency and reproducibility of decision making within forensic science.

Opportunistic crimes: Evaluation of DNA from regularly-used knives after a brief use by a different person.

When evaluating trace DNA recovered from evidential items in forensic casework, it is crucial to consider how the DNA got there, and such evaluative interpretations should ideally be informed by published experimental data. A key activity-level question is whether the DNA obtained comes from the regular user, the last user (ostensibly the user at the time of the crime) or from indirect transfer events. The aim of this experiment was to provide data to contribute to answering this question, particularly when considering opportunistic crimes, in which an offender might grab the nearest item at hand required for their purpose, e.g. a weapon or tool, and therefore only handle it very briefly. Volunteers ('regular users') used knives in a prescribed manner to simulate regular use (one user per knife); DNA recovery by mini-tapes from these knives gave ˜1-10 ng DNA, with <16% non-donor DNA from indirect transfer events. Different volunteers ('second users') then stabbed replicate sets of regularly-used knives into a foam block for either 2, 30 or 60 s (on different occasions), with each timeframe in triplicate, and DNA was recovered from the knife handles using mini-tapes. For knives regularly-used by three of the four volunteers, the ratios of regular user to second user DNA were approximately 4:1, 2:1 and 1:1 for durations of use by the second user of 2, 30 and 60 s, respectively. Analysis of the respective quantities of DNA showed that this trend resulted from a decrease in regular user DNA via transfer to the second user's hands, rather than an increase in DNA deposition from the second user. However, for knives regularly-used by the fourth volunteer, DNA from the regular user remained at significantly higher quantities than DNA from the second user and unknown sources, irrespective of duration of use by the second user. Furthermore, one volunteer deposited a similar amount of DNA through regular use as the amount of indirectly-transferred unknown DNA deposited by another volunteer's hands. These observations indicate that caution should be taken when relying solely on absolute quantities of DNA to inform evaluative interpretations, and other parameters, such as profile quality and relative contributions to mixed profiles, should also be taken into account. To better assist activity level assessments, more extensive studies of this manner should be conducted to obtain probability distributions of different types of profiles resulting from this kind of activity.

Fragrance transfer between fabrics for forensic reconstruction applications.

Sexual assault is a serious crime that often has low conviction rates. Recent literature has demonstrated that there is potential for fragrances to be valuable in forensic reconstructions where there has been contact between individuals. However, developing appropriate evidence bases for understanding the nature of fragrance transfer in these contexts is needed. This article presents three experiments that address the transfer process of fragrances that have been transferred from a primary piece of fabric onto a secondary piece of fabric, in a manner that could occur during an assault. The three variables studied were the ageing time of the fragrances on the first fabric prior to transfer, the contact time between the two fabrics, and lastly the fabric type (of the primary material and the recipient material). The transfer was evaluated using a validated solid phase micro-extraction gas chromatography-mass spectrometry (SPME GC-MS) method. The findings demonstrated that all three variables had an impact on the transfer of fragrances between clothing fabrics. Generally, lower volatility compounds were transferred and recovered in larger amounts than higher volatility compounds. All fragrance compounds were successfully recovered from a secondary piece of fabric even when the contact time was as short as 10 s, and even when the perfume was aged on the primary fabric for as long as 48 h. The nature of the fragrance transfer also depended on the fabric type, so that a clear discrimination was observed between the fragrance transfer that occurred onto a natural fabric (cotton) and onto a synthetic fabric (polyester).

Journey history reconstruction from the soils and sediments on footwear: An empirical approach.

The value of environmental evidence for reconstructing journey histories has significant potential given the high transferability of sediments and the interaction of footwear with the ground. The importance of empirical evidence bases to underpin the collection, analysis, interpretation and presentation of forensic trace materials is increasingly acknowledged. This paper presents two experimental studies designed to address the transfer and persistence of sediments on the soles of footwear in forensically relevant scenarios, by means of quartz grain surface texture analysis, a technique which has been demonstrated to be able to distinguish between samples of mixed provenance. It was identified that there is a consistent trend of transfer and persistence of sediments from hypothetical pre-, syn- and post-crime event locations across the sole of the shoe, with sediments from 'older' locations likely to be retained in small proportions. Furthermore, the arch of the shoe (the area of lowest foot pressure distribution) typically (but not exclusively) retained the highest proportion of grain types from previous locations including the crime scene. A lack of chronological layering of the retained sediments was observed indicating that techniques that can identify the components of mixed provenance samples are important for analysing footwear sediment samples. It was also identified that the type of footwear appeared to have an influence on what particles were retained, with high relief soles that incorporate recessed areas being more likely to retain sediments transferred from 'older' locations from the journey history. In addition, the inners of footwear were found to retain sediments from multiple locations from the journey history that are less susceptible to differential loss in comparison to the outer sole. These findings provide important data that can form the basis for the effective collection, analysis and interpretation of sediments recovered from both the outer soles and inners of footwear, building on the findings of previously published studies. These data offer insights that enable inferences to be made about mixed source sediments that are identified on footwear in casework, and provide the beginnings of an empirical basis for assessing the significance of such sediment particles for a specific forensic reconstruction.

A Comparison of Thresholding Methods for Forensic Reconstruction Studies Using Fluorescent Powder Proxies for Trace Materials.

Image segmentation is a fundamental precursor to quantitative image analysis. At present, no standardised methodology exists for segmenting images of fluorescent proxies for trace evidence. Experiments evaluated (i) whether manual segmentation is reproducible within and between examiners (with three participants repeatedly tracing three images) (ii) whether manually defining a threshold level offers accurate and reproducible results (with 20 examiners segmenting 10 images), and (iii) whether a global thresholding algorithm might perform with similar accuracy, while offering improved reproducibility and efficiency (16 algorithms tested). Statistically significant differences were seen between examiners' traced outputs. Manually thresholding produced good accuracy on average (within ±1% of the expected values), but poor reproducibility (with multiple outliers). Three algorithms (Yen, MaxEntropy, and RenyiEntropy) offered similar accuracy, with improved reproducibility and efficiency. Together, these findings suggest that appropriate algorithms could perform thresholding tasks as part of a robust workflow for reconstruction studies employing fluorescent proxies for trace evidence.