A preliminary study on the stability of bare footprint linear measurements in four motion states.

In some crime scenes, there may be bare footprints. Analyzing and testing the linear measurements of bare footprints in crime scenes can play an important role in personal analysis and individual identification. However, the linear measurements of bare footprints may be influenced by different motion states, leading to changes in length and width or even significant deviations. Previous studies focused on the linear differences between static and dynamic footprints, and failed to take the speed factor into consideration. This paper studied the stability and change regularities of the linear measurements of bare footprints in four different motion states: standing, normal walking, fast walking and trotting. Dust footprints of the right feet were collected from 80 healthy young adults under these four motion states. Seven linear measurements were obtained for each footprint using the Reel method, totaling 2240 data sets. One-way repeated measures ANOVA was used to assess the measurement variations across the four states. The results showed that there were statistically significant variances in the length measurements (A1-A5) between the standing state and other motion states, whereas no statistically significant variances were observed between the three dynamic states. It was found that the mean values of the five length measurements (A1-A5) increased from static to dynamic state, and then gradually decreased slightly as the walking speed increased. Additionally, no significant differences were found in the two width measurements (MPJ Width and Calc Width) between the four motion states. As a preliminary study, this study can provide a reference for the analysis of bare footprints in different motion states extracted from crime scenes.

Innovations in forensic science: Comprehensive review of hyperspectral imaging for bodily fluid analysis.

Hyperspectral imaging (HSI) has become a crucial innovation in forensic science, particularly for analysing bodily fluids. This advanced technology captures both spectral and spatial data across a wide spectrum of wavelengths, offering comprehensive insights into the composition and distribution of bodily fluids found at crime scenes. In this review, we delve into the forensic applications of HSI, emphasizing its role in detecting, identifying, and distinguishing various bodily fluids such as blood, saliva, urine, vaginal fluid, semen, and menstrual blood. We examine the benefits of HSI compared to traditional methods, noting its non-destructive approach, high sensitivity, and capability to differentiate fluids even in complex mixtures. Additionally, we discuss recent advancements in HSI technology and their potential to enhance forensic investigations. This review highlights the importance of HSI as a valuable tool in forensic science, opening new pathways for improving the accuracy and efficiency of crime scene analyses.

The smallest traces of crime: Trace elements in forensic science.

BACKGROUND: Securing the evidence in various investigative situations is often associated with trace analysis, including fingerprints or blood groups. However, when classic and conventional methods fail, trace elements, such as copper, zinc, fluorine, and many others found in exceedingly insignificant amounts in organisms, may prove useful and effective. METHODS: The presented work reviews articles published between 2003 and 2023, describing the use of trace elements and the analytical methods employed for their analysis in forensic medicine and related sciences. RESULTS & CONCLUSION: Trace elements can be valuable as traces collected at crime scenes and during corpse examination, aiding in determining characteristics like the sex or age of the deceased. Additionally, trace elements levels in the body can serve as alcohol or drug poisoning markers. In traumatology, trace elements enable the identification of various instruments and the injuries caused by their use.

The Role of Bloodstain Pattern Analysis (BPA) in Reconstructing the Dynamics of Forensic Cases.

Background: Bloodstain Pattern Analysis (BPA) is a forensic scientific discipline used to resolve criminal events. By studying the size, shape, and distribution of the bloodstains that constitute one or more bloodstain patterns, it is possible to determine the physical events responsible for their creation, as well as the positions and movements of the victim and, in cases of homicide, the perpetrator during the act. Materials and Methods: BPA analysis was applied as a support in the reconstruction of the event dynamics in four forensic cases, in addition to the data collected during on-site inspections and instrumental investigations including PMCT, autopsies, histological, and toxicological analyses. Particularly laborious was its application in a case involving a decomposed body. In all cases, a thorough photographic analysis of the bloodstains found on the clothing worn as well as in the areas surrounding the location of the corpse was conducted. Conclusions: The combination of investigations, together with the data derived from the application of BPA, allowed events to be attributed to: homicide by blunt force trauma; homicide-suicide using a bladed weapon; homicide using firearms; unplanned complex suicide. The analysis of the cases presented highlights the importance of a multidisciplinary approach through the use of additional instrumental and specialist investigations such as the study of bloodstains present at the crime scene for the reconstruction of criminal events.

Homicide by drowning: a literature review and analysis of three cases.

Background: Homicide by drowning in adults is rare. Usually, marks of violence are found on both the victim and the perpetrator, unless the victim was under the influence of alcohol, drugs, or was unexpectedly forced or dragged into the water. Indeed, many cases of drowning in adults are believed to be accidental, but they may be the result of drunken fights or attempts to make the death appear ac-cidental. In order to define the manner of death, cooperation between the forensic pathologist and the investigators is mandatory. Indeed, the autopsy is important to distinguish homicide by drowning from other kinds of drowning. The purpose of this study is to highlight the features of homicide by drowning. Materials and Methods: Literature search was conducted using PubMed databases, using the following keywords: "(homicide) and (drowning)". 3 articles were included in the systematic review, in addition to 3 cases observed in our institute. Conclusions: Both external examination and autopsy findings and the results of the investigation are essential to differentiate a homicide by drowning from accidental ones. The low specificity and variability of external and internal findings, the possibility of atypical asphyctic and nonasphyctic pathophysiological mechanisms, whose nature is not detectable at postmortem examinations, makes the diagnosis of cause of death difficult and often based on exclusion criteria only. In complex cases only using a strict forensic method allows to use the essential tools to identify the real manner of death.

The role of operative protocols for the prevention of occupational infectious risk on the crime scene.

Background: Crime scenes are possible scenario of accidents for operators, despite those risks the are no operative protocols in literature. However, COVID-19 pandemic has affected in a positive manner the management of infectious risk, encouraging use of Personal protective equipment (PPE). The aim of the study is to deepen and examine the occupational risk of all health professionals involved in the analysis of the crime scene and biological material collection to develop an operational protocol that explains in detail all the strategies applicable to reduce it. Materials and Methods: We conducted a review of the literature researching among the main databases, such as: PUBMED, EMBASE, COCHRANE introducing as keywords: crime scene, medico-legal investigations, occupational risk, infections. Subsequently, we developed an operational protocol that is currently applied during the activity of the Institute of Forensic Medicine "Magna Graecia" of Catanzaro. Conclusion: The crime scene can show numerous dangers for operators, due to the presence of syringes, contaminated biological material or sharps or access to areas with poor hygienic and sanitary conditions. This paper shows various strategies that may be implemented to reduce the risk. The aim of this work is to focus on the occupational risk for operators by proposing an operative protocol showing in detail how to manage a crime scene by reducing the infectious risk for operators until the transfer of the body and the collected evidence to the morgue and to the laboratory.

A stain with all the fixing's - Enhancement of fingermarks in blood using a combined fixative and aqueous protein stain.

The use of protein stains to enhance fingermark ridge detail in blood is a common technique used by forensic practitioners around the world. Amido Black is one of the most favoured protein stains due to its strong staining ability. The most common formulation of Amido Black is methanol based, with an ability to simultaneously fix and stain the blood impression, however methanol is toxic and can disrupt some surfaces, potentially compromising fingermark detail. If the surface is suspected of being a material that is impacted by methanol, there is an alternative aqueous formulation, which requires a fixative step to set the blood prior to staining so as not to wash away potential ridge detail. The multi-step process of aqueous protein stains is tedious and numerous studies have been conducted to improve the formula to achieve a combined fixing/staining solution that performs like the methanolic reagent. A combined fixative and stain formulation of aqueous based Amido Black was compared to a multi-step formulation with a separate sulfosalicylic acid fixative. Of the 243 split fingermark impressions analysed the majority (63.5 %) showed no preference to either treatment, with a marginally greater proportion of the remaining marks slightly favouring the combined fixative and stain formulation. Given that the new combined formulation performed broadly similarly to the existing multi step formulation, the potential time savings of this simpler approach may be beneficial to implement into operational use.

Forensic species identification: practical guide for animal and plant DNA analysis.

The importance of non-human DNA in the forensic field has increased greatly in recent years, together with the type of applications. The molecular species identification of animal and botanical material may be crucial both for wildlife trafficking and crime scene investigation. However, especially for forensic botany, several challenges slow down the implementation of the discipline in the routine.Although the importance of molecular analysis of animal origin samples is widely recognized and the same value is acknowledged to the botanical counterpart, the latter does not find the same degree of application.The availability of molecular methods, especially useful in cases where the material is fragmented, scarce or spoiled preventing the morphological identification, is not well known. This work is intended to reaffirm the relevance of non-human forensic genetics (NHFG), highlighting differences, benefits and pitfalls of the current most common molecular analysis workflow for animal and botanical samples, giving a practical guide. A flowchart describing the analysis paths, divided in three major working areas (inspection and sampling, molecular analysis, data processing and interpretation), is provided. More real casework examples of the utility of non-human evidence in forensic investigations should be shared by the scientific community, especially for plants. Moreover, concrete efforts to encourage initiatives in order to promote quality and standardization in the NHFG field are also needed.

The impact of climate change on the crime scene and forensic sciences.

Background: Climate change causes great impact on ambient temperatures. In forensic pathology, temperature has always been an important variable to determine numerous thanatodiagnostic and thanatochronological parameters, as crucial elements to make scientifically valid forensic conclusions. The aim of this work is to describe the impact that climate change is having on the forensic science and crime scene analysis. Materials and methods: A literature review was carried out on the search engines Pubmed, Scopus and Google Scholar. The keywords "climate change" AND "forensic" were used. Conclusion: Climate change is having a significant impact on forensic science in several areas. Among these it is necessary to consider: 1) global warming and crime scenes: high temperature of the planet causes frequent extreme meteorological events in multiple periods of the year; 2) Relationship between climate and PMI (Post Mortem Interval): Temperature influences the rapidity of putrefaction; 3) Relationship between climate and fauna: global warming is influencing the geographical distribution of animal species, with real migrations of species. Fauna has a decisive impact in the forensic field (as in the case of entomology) creating new models of animal-cadaver interaction; 4) Relationship between climate and forensic botany: Climate change influences the flowering and fruiting times of plants, impacting knowledge on botany used in the forensic field. It is essential to adopt prevention measures to address the emerging challenges.

Comparative Toxicological Analyses of Traditional Matrices and Blow Fly Larvae in Four Cases of Highly Decomposed Human Cadavers.

In forensic investigation, determining the time and cause of death becomes challenging, especially in cases where the remains are found in advanced decomposition, rendering traditional toxicological samples unavailable or unreliable. Entomotoxicology, an emerging methodology within forensic science, leverages insect specimens collected from cadavers as alternative toxicological samples. Several laboratory and field research studies have highlighted the efficacy in detecting various drugs, toxins, and elements absorbed by insects feeding on cadaveric tissues, even at low concentrations. However, correlation studies between drug concentrations in conventional matrices and insects remain controversial due to unknown factors influencing drug metabolism and larval feeding activity. This paper presents four real cases in which human cadavers were discovered in advanced stages of decomposition, and toxicological analyses were performed on both insect samples and available matrices. The results presented complement the scant literature currently available on the application of entomotoxicology in real cases, providing insights into the correlation between larvae and human specimen results. Furthermore, guidelines to collect and preserve entomological evidence at the crime scene and during the autopsy for use in entomotoxicological analyses are provided. This advancement holds promise in aiding forensic investigations, particularly in cases where traditional methods cannot be applied or require supporting data for further validation.

Understanding sexual homicide in Korea using machine learning algorithms.

The current study was conducted to confirm the characteristics in sexual homicide and to explore variables that effectively differentiate sexual homicide and nonsexual homicide. Further, newer methods that have received attention in criminology, such as the machine learning method, were used to explore the ideal algorithm for classifying sexual homicide and patterns for sexual homicide in Korea. To do this, 542 homicide cases were analyzed utilizing eight algorithms, and the classification performance of each algorithm was analyzed along with the importance of variables. The results of the analysis revealed that the Naive Bayes, K-Nearest Neighbors, and RF algorithms demonstrate good classification accuracy, and generally, factors such as relationships, marriage, planning, personal weapons, and overkill were identified as crucial variables that distinguish sexual homicide in Korea. In addition, the crime scene information of the crime occurring in the dark (at night) and body disposal were found to have high importance. The current study proposes ways to enhance the efficacy of crime investigation and advance the research on sexual homicides in Korea through a more scientific understanding of sexual homicide that has not been thoroughly explored domestically.

A review of the contributions of forensic archaeology and anthropology to the process of disaster victim identification.

Forensic archaeology and anthropology have developed significantly over past decades and now provide considerable assistance to the investigation process of disaster victim recovery and identification. In what are often chaotic death and crime scenes, the formal process of utilizing archaeological methods can bring control, order, and ensure systematic search. Procedures assist in defining scene extent, locating victims and evidence, rule out areas for consideration, and provide standardized recording and quality assurance through dedicated use of standardized forms (pro formas). Combined archaeological and anthropological search methods maximize opportunities to recovery the missing through identifying remains, mapping distributions, and providing accounting of victims at the scene. Anthropological assistance in examinations contributes to individual assessment, resolving commingling and fragmentation issues, and utilizing DNA sampling methods and matching data to reassociate and account for the missing. Utilization of archaeology, anthropology, and DNA matching data provides scope to review crime scene recovery and determine requirements and potential for further survey and retrieval. Adopting the most suitable methods for a particular context can maximize recovery, efficiency, and resource use. Case studies demonstrate the utility of archaeological methods in a range of scenarios. They exemplify the success of multidisciplinary analysis in providing evidence of the sequence of events, the timing of events, the impact of taphonomic processes, the location and accounting of victims, and the demonstration of systematic scene search. The considerations provided in this article, utilizing archaeology and anthropology processes, may assist investigators in planning and implementing responses to mass fatalities.

The Evaluation of Artificial Intelligence Technology for the Differentiation of Fresh Human Blood Cells From Other Species' Blood in the Investigation of Crime Scenes.

OBJECTIVES: The current study used the deep machine learning approach to differentiate human blood specimens from cow, goat, and chicken blood stains based on cell morphology. METHODS: A total of 1,955 known Giemsa-stained digitized images were acquired from the blood of humans, cows, goats, and chickens. To train the deep learning models, the well-known VGG16, Resnet18, and Resnet34 algorithms were used. Based on the image analysis, confusion matrices were generated. RESULTS: Findings showed that the F1 score for the chicken, cow, goat, and human classes were all equal to 1.0 for each of the three algorithms. The Matthews correlation coefficient (MCC) was 1 for chickens, cows, and humans in all three algorithms, while the MCC score was 0.989 for goats by ResNet18, and it was 0.994 for both ResNet34 and VGG16 algorithms. The three algorithms showed 100% sensitivity, specificity, and positive and negative predictive values for the human, cow, and chicken cells. For the goat cells, the data showed 100% sensitivity and negative predictive values with specificity and positive predictive values ranging from 98.5% to 99.6%. CONCLUSION: These data showed the importance of deep learning as a potential tool for the differentiation of the species of origin of fresh crime scene blood stains.

Uncovering Forensic Evidence: A Path to Age Estimation through DNA Methylation.

Age estimation is a critical aspect of reconstructing a biological profile in forensic sciences. Diverse biochemical processes have been studied in their correlation with age, and the results have driven DNA methylation to the forefront as a promising biomarker. DNA methylation, an epigenetic modification, has been extensively studied in recent years for developing age estimation models in criminalistics and forensic anthropology. Epigenetic clocks, which analyze DNA sites undergoing hypermethylation or hypomethylation as individuals age, have paved the way for improved prediction models. A wide range of biomarkers and methods for DNA methylation analysis have been proposed, achieving different accuracies across samples and cell types. This review extensively explores literature from the past 5 years, showing scientific efforts toward the ultimate goal: applying age prediction models to assist in human identification.

Application of augmented reality for crime scene investigation training and education.

The role of the crime scene investigator is complex, and investigators need to be able to conduct multiple frequently performed tasks. Appropriate training and education are critical to impart the crime scene investigator with the necessary capabilities. For a range of reasons, including the COVID-19 pandemic and the need for multi-disciplinary capabilities, training and education requirements have evolved in recent times to be more flexible and accessible. The skills of a crime scene investigator can be broadly categorised into two types of fundamental skills: decision-making and psychomotor skills. Both these skills need to be taught and assessed within training and education programs. The most common approach to impart these skills is by incorporating a crime scene simulation facility; however, not everyone has access to these facilities. Furthermore, crime scene staff often undertake refresher courses and are required to complete proficiency assessments. Conducting these activities in a dedicated crime scene simulation facility is time consuming and costly. Virtual tools have been developed in recent years to address this, but these tools only assess decision-making skills and not psychomotor skills. This paper argues that the implementation of augmented reality (AR) technology should be considered in crime scene investigator training and university education, because it can provide significant advantages when paired with conventional methods of training and education. When appropriately managed, AR can provide an avenue of training where both decision-making and psychomotor skills can be addressed simultaneously, while providing a more flexible and accessible approach. The implementation of AR has the potential to significantly improve the standards of teaching, resulting in better equipped crime scene investigators. The paper will explore how AR has the potential to improve accessibility of training, increase safety, enhance the student experience, enhance collaboration and feedback through connectivity and potentially reduce cost. This paper will also provide an insight into what would need to be considered before implementing AR technology into crime scene investigation training and education alongside current approaches. It is argued that the inclusion of AR into the current training and education arsenal provides significant benefits that are worthy of exploration.

3D scanning a crime scene to enhance juror understanding of Bloodstain Pattern Analysis evidence.

There are numerous crime scene investigation applications of 3D scanning that have been previously documented. This paper documents the application of a 3D point cloud in the presentation of Bloodstain Pattern Analysis evidence to mock jurors. 150 mock jurors viewed a presentation of Bloodstain Pattern Analysis evidence from a murder trial in the UK. After viewing the evidence, the participants were tested on their knowledge of the evidence and repeated the test again 2 weeks later; to simulate criminal trial conditions; whereby there is a time lapse between the initial viewing of evidential material and deliberation. This paper found that the mock jurors who additionally viewed a 3D flythrough of a point cloud of the crime scene, better retained knowledge of the evidence over time, reported a greater ability to visualise the crime scene and had higher levels of interest in the evidence. Crucially, the 3D flythrough group did not report different levels of confidence in the accuracy of their memories of the evidence, nor different levels of emotional arousal to the group that viewed the evidence without the 3D presentation. Together, these findings suggest that 3D scanning of crime scenes, and the resultant point cloud's presentation to jurors, could add further value to the justice system when spatial information, such as Bloodstain Pattern Analysis evidence, is presented.

Crime-scene and offender characteristics in conventional and nonconventional stranger homicides committed by male offenders in Sweden.

In Sweden, from 1990 to 2013, most homicides occurred between family members, friends or acquaintances: the annual rate of incidents between unacquainted offenders and victims ranged between 8% and 13%. In the majority of these "stranger homicides," three common motives, as defined by the precipitating event, could be identified: homicides resulting from a spontaneous altercation; homicides committed in the context of a robbery or burglary; and homicides committed in the context of a gangland conflict. The remaining minority-with uncommon or indiscernible motives-could, nonetheless, be categorized according to their nonconventional distinguishing feature: homicides characterized by the offender's ostensibly mentally aberrant behavior; homicides committed in the context of a hate offense or politically motivated offense; homicides committed in the context of a sexual offense; and homicides committed in the context of a mass killing or series of homicides. In this registry-based study of 224 incidents, "conventional" stranger homicides, defined by their commonplace motive, were compared with "nonconventional" stranger homicides, defined by their lack of such motive. The former were more often committed with an accomplice, against a male victim, whereas the latter were more often committed in a public place, after contact initiated by the offender. In the latter, offenders were less often intoxicated at the time of the offense and more often adjudged to suffer from a severe mental disorder. The subcategory of nonconventional stranger homicides characterized by the offender's ostensibly mentally aberrant behavior corresponded largely to both the archetypal stranger-homicide construct and the popular notion "act of madness."

Detrimental effects of scene manipulations on temperature-based time since death estimation.

In forensic casework, time since death (TSD) estimations may play a crucial role to establish chains of events as well as for alibi assessment in homicide cases. Classical TSD estimation relies on reasonably stable ambient temperatures and a correct documentation of ambient and rectal temperatures. This constancy is in some cases disturbed by post-discovery alterations of the crime scene, e.g. opening a window. In order to develop a better understanding of this alteration-based detrimental impact on TSD estimation as well as to identify feasible recommendations for casework, the present pilot study examined ambient temperature effects of different window opening scenarios regarding various time intervals (5 to 360 min) in a furnished 10 m2 apartment during winter. In this context, in addition to the ambient temperature and thus the cooling rate of the room, re-approximation to initial room temperature, potential influences on a nomogram-based time since death estimation using a fictitious case, and the impact of the measurement height above the ground were investigated. Our data indicate a significant reduction of the mean temperature decrease rate after 15 min regardless of the remaining opening time and a correlation with the size of the respective opening surfaces. Re-approximation to initial room temperatures was observed with up to three times longer than the initial opening time. There was no evidence of a substantial advantage of temperature measurements above the level of the corpse (> 0.1 m). The limitations of the study and its applicability for forensic casework are critically reviewed.

Sexual dimorphism and topological variability in fingerprint ridge density in a north-west Indian population.

The science of fingerprints is very crucial in criminal investigation as it helps identify perpetrators or victims of a crime. Fingerprint ridge density (FPRD), which refers to the number of ridges within a specific area on the epidermal skin layer of the distal phalanges in humans, has been found to differ between males and females. This study attempts to estimate the sex from FPRD and evaluates the diversity in FPRD across several topological areas. The study involves 208 participants (120 males, 88 females) between the ages 18 to 25 years from a North-west Indian population. Fingerprints were collected, and FPRD was accessed in radial, ulnar, and proximal areas as recommended by Gutierrez-Redomero et al. (Forensic Sci Int 180(1):17-22, 2008). FPRD has been quantified using the techniques described by Acree (Forensic Sci Int 102(1):35-44, 1999). When evaluating FPRD in the lateral pocket loops and twin loops, the proximal-side core was considered. The study reveals that males have a mean fingerprint ridge density of 12.82 ridges/25 mm2 while females have 13.01 ridges/25 mm2. Females have higher fingerprint ridge density solely in the proximal area; males have higher fingerprint ridge density in both radial and ulnar areas. In conclusion, this research underscores the potential of fingerprint ridge density as a parameter for investigating population variations and individual identification. Future studies on fingerprint ridge density in India's diverse population will help establish reference ranges, allowing for sex and likely population group estimation, making it a valuable tool for preliminary examinations and exclusion criteria for sex estimation in crime scene investigations.

Spatial relationships among offender, knife, and victim during slashing attacks: implications for crime scene reconstruction.

BACKGROUND: The offender-victim spatial relationship is crucial in reconstructing a crime scene. The study aims to evaluate the spatial relationship of performing slashing attacks on a dummy using a Chinese kitchen knife, and thus to establish a scientific basis for crime scene reconstruction. METHODS: Twenty-four participants (12 males and 12 females) slashed a dummy's neck or chest using a kitchen knife, and the kinematic data were obtained using a three-dimensional motion capture system. The spatial relationships among offender, knife, and victim during slashing attacks were analyzed. RESULTS: Slashing distance and occupancy area are significantly influenced by gender (all P < 0.05), with males having higher values than females. Body parts significantly influence bevel angle, offender and victim azimuth angles, slashing distance, relative slashing distance, and occupancy area (all P < 0.01), with slashing the chest resulting in larger values than slashing the neck. CONCLUSION: Gender and body position significantly influence the spatial relationships of slashing action. Our data indicate that males stand farther away and occupy a larger area during slashing attacks. When the chest is slashed, the wound orientation is more diagonal, the offender's standing position and slashing distance are farther, and the occupancy area is larger compared to the neck. The findings could help identify the spatial relationships among offender, knife, and victim, providing a scientific basis for criminal investigations and court trials.