Application of 3D documentation and geometric reconstruction methods in traffic accident analysis: with high resolution surface scanning, radiological MSCT/MRI scanning and real data based animation

The examination of traffic accidents is daily routine in forensic medicine. An important question in the analysis of the victims of traffic accidents, for example in collisions between motor vehicles and pedestrians or cyclists, is the situation of the impact. Apart from forensic medical examinations (external examination and autopsy), three-dimensional technologies and methods are gaining importance in forensic investigations. Besides the post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) for the documentation and analysis of internal findings, highly precise 3D surface scanning is employed for the documentation of the external body findings and of injury-inflicting instruments. The correlation of injuries of the body to the injury-inflicting object and the accident mechanism are of great importance. The applied methods include documentation of the external and internal body and the involved vehicles and inflicting tools as well as the analysis of the acquired data. The body surface and the accident vehicles with their damages were digitized by 3D surface scanning. For the internal findings of the body, post-mortem MSCT and MRI were used. The analysis included the processing of the obtained data to 3D models, determination of the driving direction of the vehicle, correlation of injuries to the vehicle damages, geometric determination of the impact situation and evaluation of further findings of the accident. In the following article, the benefits of the 3D documentation and computer-assisted, drawn-to-scale 3D comparisons of the relevant injuries with the damages to the vehicle in the analysis of the course of accidents, especially with regard to the impact situation, are shown on two examined cases.     

Geomatic techniques in forensic science: A review

The purpose of this review paper is to highlight various geomatic techniques that crime scene reconstructionists or forensic practitioners can use to document different kinds of scenes, highlighting the advantages, disadvantages, and when best to use each technology. This paper explores geomatic techniques such as a total station, photogrammetry, laser scanners and structured light scanners and how they can be used to reconstruct crime scenes. The goal of this paper is not to discredit manual methods, as they are long standing and reliable, but instead to shed light on alternative methods that may produce equally or more accurate results with a more visually appealing final product. It is important for law enforcement and forensic professionals to understand the advantages and disadvantages of each technique, knowing when certain techniques should be used (and when they should not), and being able to revert to traditional methods if required.     

The development and application of a diatom-based quantitative reconstruction technique in forensic science

Diatoms are a group of unicellular algae that have been recorded and classified for over 200 years and have been used in a range of applications in forensic science. We have developed a quantitative diatom-based reconstruction technique to confirm drowning as a cause of death and localize the site of drowning in two recent, high-profile, case studies. In both case studies we collected diatom samples from the local and/or regional area to act as a control in the examination of diatom assemblages associated with lungs and clothing. In Case Study 1 the modern analog technique suggested that all lung and clothing samples have statistically significant similarities to control samples from shallow water habitats. In Case Study 2, the analog matching suggested that the majority of lung samples show a statistically significant relationship to samples from a pond, indicating that this was the drowning medium.     

Inference structures for crime analysis and intelligence: the example of burglary using forensic science data

There has been much work dedicated to crime analysis and intelligence in recent times. Independently, physical evidence has shown great potential for linking crimes and bringing solid informative data through the increased use of multiple databases. However, their informative potential is still often underestimated and has been poorly integrated into police information systems. We propose a framework that fully introduces this data into an intelligence based system. This framework is built on the study of inference structures extracted from investigators’ every day implicit reasoning processes. Five specific inferences are studied with the particular problem of serial burglary investigation across independent police and legal structures. On the basis of such an analytical approach, a computer prototype has been designed; it has shown great promise and has resulted in several operational successes.     

Beyond CSI: Calibrating public beliefs about the reliability of forensic science through openness and transparency

What drives public beliefs about the credibility of a scientific field? This question is increasingly important, with recent discussion of a “reproducibility crisis” affecting many fields. Such discussions are vital in forensic science, a discipline that has experienced severe scrutiny from both the media and large oversight bodies. In this paper, we make three contributions to this discussion. First, we bring together and compare several studies in which laypeople were asked about the reliability of forensic science practices. This review suggests that forensic practices do not enjoy uniformly high reliability ratings from the public and these ratings are not calibrated with the scientific consensus. We then review three empirically-tested ways that other fields are dealing with their own crises, all centred around transparency and openness. Finally, we make recommendations for how forensic science can leverage transparency and openness to improve and maintain its long-term credibility. As part of these recommendations, we find that empirical research supports the Houston Forensic Science Center’s recent claims that it has improved its credibility through openness and transparency.     

The distinction between discriminability and reliability in forensic science

Forensic science plays an increasingly important role in the criminal justice system; yet, many forensic procedures have not been subject to the empirical scrutiny that is expected in other scientific disciplines. Over the past two decades, the scientific community has done well to bridge the gap, but have likely only scratched the tip of the iceberg. We offer the discriminability-reliability distinction as a critical framework to guide future research on diagnostic-testing procedures in the forensic science domain. We argue that the primary concern of the scientist ought to be maximizing discriminability and that the primary concern of the criminal justice system ought to be assessing the reliability of evidence. We argue that Receiver Operating Characteristic (ROC) analysis is uniquely equipped for determining which of two procedures or conditions has better discriminability and we also demonstrate how estimates of reliability can be extracted from this Signal Detection framework.     

生物超弱发光在法医学中的研究应用展望

生物超弱发光携带着生物体新陈代谢和能量转化的信息,已成为生命学科的重要研究领域。本文回顾生物超弱发光的研究历史、特点及在医学领域的研究应用现状,展望生物超弱发光在法医学,尤其是死亡时间推测和损伤方面的研究应用前景     

The use of simulated crime scenes in teaching undergraduate forensic sciences: Implementing an active learning approach to forensics

Incorporating a simulated crime scene into one’s pedagogy in forensic science undergraduate courses allows students the opportunity to experience a realistic scenario while demonstrating their knowledge and enhancing their critical thinking skills. The purpose of this paper is to examine an active learning approach to using simulated crime scenes to provide an impactful learning experience for students. While potentially challenging for the instructor, constructing a crime scene scenario can provide students with hands-on practical experience while helping to dispel forensic science misconceptions. Through many years of creating crime scenes, best practices for using such high impact activities in forensic science courses are described in detail, including preparatory exercises that culminate in the final crime scene scenario, considerations in preparing and constructing a crime scene activity, and supervising and assessing students once the activity begins. Three major challenges to implementing active learning exercises such as simulated crime scenes in undergraduate forensic science programs include high workload for instructors, limited supplies, and lack of suitable facilities. Workload solutions include instructors and departments considering the cost and benefit of course releases to improve curriculum and student enrollment. Supplies and facilities solutions involve innovation in reuse and repurposing of supplies, and instructor flexibility in using classroom and outdoor spaces.     

Interdisciplinary approaches to the teaching of forensic science in the Forensic Science Undergraduate Program of the National Autonomous University of Mexico,before and after COVID-19

In 2013, the Forensic Science Undergraduate Program (FSUP) at the National Autonomous University of Mexico was created in response to an alarming criminal situation in Mexico, as well as to the radical reform of its criminal justice system. Its mission is to educate and train ethical, critical, and humanistic forensic scientists capable of conducting inquiries that meet scientific quality standards and assist the justice system in firmly linking legal rulings to the available evidence. At the time, it was the first such program in the country, and the contributions that interdisciplinary forensic scientists could make to criminal investigations were largely unknown among forensic and legal practitioners. During its existence, providing an interdisciplinary, competence-based education to students has been one of the main challenges. To overcome it, teaching and assessment approaches—centered on the achievement of specifically forensic competencies as learning outcomes and the integration of forensic disciplines towards the resolution of simulated cases—have been devised to help develop the professional skill set expected of graduates. The COVID-19 pandemic led to adapting these approaches to distance or hybrid modes of learning, increasing their versatility and enriching the pedagogic repertoire of the FSUP. Currently, the main impact of the program lies in the successful incorporation of some of its graduates to agencies belonging to or related to the criminal justice system, such as the National Prosecutor’s Office, the Commission for Truth and Justice for the Ayotzinapa Case, and the National Commission for the Search of Missing and Disappeared Persons, among others.     

Measuring the impact of forensic science in detecting burglary and autocrime offences

As UK investment in forensic science has increased, the government has taken a fresh interest in how far this has led to dividends in terms of the detection of crime and its reduction. The Home Office funded 'Pathfinder Project' sought to monitor and document the complex relationships between the collection and use of forensic material (looking at a range of forensic science techniques) and its impact on crime detection. The project specifically targeted the 'volume' crimes of burglary and vehicle crime. Detailed data was gathered on all stages of the process between the collection and use of forensic material and crime detection. The model falls into two conceptual phases--scene attendance to suspect identification and identification to detection. From the analysis it was found that approximately one third of burglary and autocrime scenes are visited by SOCOs. While scientific identifications are only made in a minority of burglary and autocrime offences overall, it belies their importance. About one in ten of burglary and autocrime cases are cleared up by the police and it is estimated that fingerprints and SGMPlus were a contributory factor in achieving one third of these clear ups.     

A preliminary study into the impact of using three-dimensional models in forensic anthropology learning and teaching

Forensic anthropology has traditionally relied on two-dimensional (2D) images, such as photographs and sketches, to perform analyses, and disseminate findings. However, as 3D imaging technology advances, it has become more widely implemented into forensic anthropology analysis and practice. Teaching and learning in forensic anthropology still often relies on 2D images, but increasingly three-dimensional (3D) models are available to be used by students training in anatomy and osteology. Additionally, 3D models have been found to be beneficial to comprehension in other contexts within forensic anthropology, such as in the courtroom. The use of these models in the teaching of forensic anthropology is not yet widely implemented and more importantly, the impact on learning is not yet understood. The use of 3D imaging and visualisation in other educational contexts has seen positive results, for example in medical training. To explore this further, a study was conducted using an online activity to compare the comprehension scores of students educated using 2D textbook style images or 3D models on Sketchfab. The results showed that the use of 3D images was not detrimental to comprehension. Students using the 3D models were more consistent in their performance and reported an increase in confidence regardless of prior experience. The results of this study are of particular importance when distance learning due to the COVID-19 pandemic which means that students cannot always learn in a laboratory environment.     

3D forensic facial approximation: Implementation protocol in a forensic activity

The primary objective of this paper is to report on the successful implementation of forensic facial approximation in a real case in the forensic context. A three‐dimensional (3D) facial approximation protocol of the skull was performed with free software, applying techniques in a virtual environment that have already been consolidated in the literature. The skull was scanned with the photogrammetry technique, the digital replica was imported in the Blender software (Blender Foundation, Amsterdam) and individualized model sketches of the face were traced with the MakeHuman software (MakeHuman Org) according to the anthropological profile of the victim. The face created was imported in Blender, where it was adapted, modeled, and sculpted on the 3D skull and its soft tissue markers, using an American open‐source application of the technique in the digital environment. The face created in a virtual environment was recognized and legal identification procedures were started, resulting in the more agile delivery of the disappeared body to its next of kin. It is therefore concluded that facial approximation may not be a primary method of human identification, but it can be satisfactorily applied in the forensic field as an individual recognition resource. It has great value in narrowing the search, reducing the number of alleged victims, and leading to identification tests, therefore significantly reducing the number of genetic DNA (deoxyribonucleic acid) tests—which are considered costly for the State or Federation—and consequently reducing the waiting time before delivery of the body to its family.     

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.     

Influence of the luminol chemiluminescence reaction on the confirmatory tests for the detection and characterization of bloodstains in forensic analysis

Preliminary tests for the detection of stains at crime scenes aim to focus the police work making them more efficient in the combat of criminality. The application of the luminol chemiluminescence reaction (3-aminoftalhidrazida) in presumptive tests for the detection of bloodstains is known for more than 40 years in forensic science. This reaction is based on the emission of light through the chemical reaction of luminol mixed with hydrogen peroxide and a hydroxide in the presence of a catalytic molecule (iron from the hemoglobin) (Laux [1]).This work evaluates the luminol interference and its effect on subsequent serological and DNA testing. Samples prepared with blood and different concentrations of luminol solution containing luminol, peroxide of hydrogen and sodium carbonate, were analyzed. Additionally, samples of serial dilutions of standard DNA mixed with luminol solution were also analyzed. Although presumptive tests with luminol do not establish the characterization and identification of stains at crime scenes, preliminary results indicated that it is suitable for the detection of invisible bloodstains for forensic analysis, with few detrimental effects on the serological tests and subsequent DNA recovery and typing.     

Voicing concerns: The balance between data protection principles and research developments in forensic speech science

The status of forensic speech recordings among existing data protection guidance is not clear. The inherent nature of voice and the way in which forensic speech casework is currently allocated mean that there are additional barriers to incorporating real casework data into research activities. The key objective of this work is to explore data protection solutions that could enable the forensic speech science community to responsibly use real casework data for research and development purposes. While reviewing relevant guidance and rulings, issues such as proportionality, opportunism and data minimisation are addressed, as well as where voice sits in relation to the definition of “biometric data”. This paper ultimately places forensic speech recordings in the data protection context to illuminate the specific issues that arise for this data type.     

Conceptualising,evaluating and communicating uncertainty in forensic science: Identifying commonly used tools through an interdisciplinary configurative review

This study provides a set of tools for conceptualising, evaluating and communicating uncertainty in forensic science. Given that the concept of uncertainty is one that transcends disciplinary boundaries, an interdisciplinary configurative review was carried out incorporating the disciplines of medicine, environmental science and economics, in order to identify common themes which could have valuable applications to the discipline of forensic science. Critical Interpretive Synthesis was used to develop sub-synthetic and synthetic constructs which interpreted and synthesised the underlying evidence and codes. This study provides three toolkits, one each for conceptualisation, evaluation and communication. The study identified an underlying theme concerning the obstacles that would need to be overcome for the effective application of these toolkits and achieving effective conceptualisation, evaluation and communication of uncertainty in forensic science to lay-stakeholders. These toolkits offer a starting point for developing the conversation for achieving greater transparency in the communication of uncertainty. They also have the potential to offer stakeholders enhanced understanding of the nuances and limitations of forensic science evidence and enable more transparent evaluation and scrutiny of the reliability, relevance and probative value of forensic materials in a crime reconstruction.     

Inter-observer error for area of origin analysis using FARO Zone 3D

In a bloodletting incident, the area of origin (AO) of an impact bloodstain pattern is crucial when establishing the sequence of events. The use of laser scanners and other three-dimensional (3D) technologies to document and analyse bloodstains have been the subject of previous papers, especially where AO analysis is concerned. FARO Zone 3D (FZ3D) is a relatively new software programme that can be used for bloodstain AO analysis. FZ3D requires a greater understanding of inter-observer errors associated with AO. This study looked at the inter-observer variation between 21 examiners when repeatedly calculating the AO six times for a single impact pattern on a plain white wall. An impact rig which consisted of a spring tension arm was positioned and fixed 45 cm from the X wall (right wall), and 45 cm from the Y wall (left wall). This experimental design resembles an impact blow for a bloodletting event. The AO was unknown to all examiners, making it a blind study. The collected results were documented in a Microsoft Excel datasheet and later analysed. From previous literature, a 30 cm acceptable allowance was utilised for AO analysis; however, there is currently no accepted standard error for this type of analysis. The overall total 3D mean error for all examiners was 5.62 cm. The maximum error for any one impact analysis was 24.27 cm. The variation of the data, which was collected by all examiners, was documented as X = 1.14 cm, Y = 1.24 cm, Z = 1.68 cm, and the total 3D error = 2.28 cm. The total 3D error for any one examiner and the variance between examiners did not exceed the 30 cm acceptable allowance utilised in previous literature.     

On the discrimination between facial creams of different brands using Raman Spectroscopy and partial least squares discriminant analysis for forensic application

Determining the origin of cosmetic traces is an important aspect of forensic investigations, that helps linking a suspect to a crime. Such type of evidence can help further narrow down the undergoing investigations. This paper reports the first use of Raman Spectroscopy (RS) coupled with the exploratory principal component analysis (PCA) and supervised partial least squares-discriminant analysis (PLS-DA) in facial creams. 40 facial cream samples of 8 different brands were studied in this work. Preliminary assessments through visual inspection of their Raman spectra revealed the presence of oxides, titanium dioxide, castor seed oil, and beeswax. Also, the peaks of alkyne groups were indicative of the presence of talc or mica compounds. The exploratory PCA correctly segregated the samples into 8 clusters and the supervised PLS-DA model correctly classified them into 8 classes. Further evaluation of the performance of the trained PLS-DA model resulted in perfect classification shown by the receiver operating characteristic (ROC) curves. The PLS-DA model also resulted in 100% accuracy of correctly assigning the brand on the face wipes on each of the five substrates viz. cotton, dry and wet tissue paper, nylon substrate, and polyester. This validation was done treating these samples as unknowns. The study has a potential for use under actual forensic casework conditions.