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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. [ABSTRACT FROM AUTHOR]

Textiles are one of the most frequently collected items at crime scenes. Even so, the mechanisms that create bloodstains on textiles are not well understood. This is likely due to the wide range of textiles and the many surface treatments given to them to enhance their performance. In this study, the final appearance of 50 μl passive drip stains on four in-house knitted apparel textiles (scoured cotton, hydrophobic cotton, hydrophilic polyester and hydrophobic polyester) was investigated. The yarns used to make the knits were 167 dTex polyester filament and 342 dTex cotton staple yarns. They were knitted on the same knitting machine under nominally identical conditions. The area of bloodstains on the scoured cotton knit fabrics was 46 mm2 and 30 mm2 on the hydrophobic cotton. i.e. the stains on the hydrophilic cotton were 50% larger than on the hydrophobic cotton. The bloodstains on hydrophobic polyester were only 15.6 mm2, but were 242 mm2 on hydrophilic polyester, i.e. 15 times larger. The stain areas on the polyester were both smaller (hydrophobic finish) and larger (hydrophilic finish) than on the cotton fabrics. It is shown that these typical chemical treatments play a much more important role on bloodstain areas than fibre type or fabric construction. [ABSTRACT FROM AUTHOR]

• There are at least ten different methods to classify bloodstain patterns. • Most of the current methods are mechanistic and prone to contextual bias. • A lack of clearly defined, unambiguous classification criteria is a key limitation. • An unambiguous method for bloodstain classification resolves current limitations. • Further research in statistical descriptions and fluid dynamics is required. Classifying bloodstains is an essential part of Bloodstain Pattern Analysis. Various experts have developed methods. Each method considers the same basic bloodstain pattern types. These use either terminology based on the observable characteristics or the mechanistic cause of the bloodstain patterns as part of the classification process. This review paper considers ten classification methods from fourteen sources, which are used to classify bloodstain patterns. There are fundamental differences in how the patterns are classified, how differentiated the classification is, and whether the classification process uses clear, unambiguous criteria, and is susceptible to contextual bias. Experts have also reported issues with classifying bloodstains that have indistinguishable features. These differences expose key limitations with current classification methods: mechanistic terminology is too heavily relied on, and the classification process is susceptible to contextual bias. The development of an unambiguous classification method, based on directly observable characteristics within bloodstain patterns is recommended for future work. [ABSTRACT FROM AUTHOR]

Bloodstain pattern analysis (BPA) has proven to be a useful tool in forensic and criminal investigations for quite some time. Traditionally, documenting a crime scene for a bloodletting event was completed using manual techniques, physical strings, and a tape measure. In more recent years, laser scanners and 3D software programs have become a preferred method to capture accurate data that improves the validity and reliability of BPA. The initial cost of laser scanning equipment is relatively high, rendering these systems inaccessible to some police and smaller agencies. Recon-3D is a newly developed iPhone application that utilizes the iPhone LiDAR sensor in combination with video data to create 3D point clouds of crime scenes. To assess the viability of Recon-3D for area of origin analysis, two tests were performed. One was a series of bloodstain impacts which were analyzed in FARO Zone 3D software, while the second was a series of 6 repeated Recon-3D scans of two 90-degree walls which was then compared to the FARO Focus S350 scanner using CloudCompare software. A total of eight impact patterns were made at three different distances from a wall. The area of origin was measured and compared to the known location of the blood source. The average total 3D error for the area of origin set at 25, 50, and 100 cm from two perpendicular walls was found to be 6.04, 15.16, and 36.59 cm, respectively. These results are similar to past studies where programs such as HemoSpat have been used. The results of the point cloud comparison show that on average, 95% of the points from Recon-3D fall below a threshold of 3.6 mm when compared to a FARO Focus S350 laser scanner. Thus, the results of this test suggest that Recon-3D is an accurate and affordable scanning application for bloodstain patterns at crime scenes and the data provide acceptable results for area of origin analysis in BPA programs which accept laser scanner data. [ABSTRACT FROM AUTHOR]

In bloodstain pattern analysis (BPA), a field of forensic science, there has been active discussion on the estimation of the area of origin of impact spatter. However, there is no established methodology to quantitatively analyze the area of origin of a swing cast-off pattern. To quantitatively analyze the methodology of previous research on estimation of area of origin, a device for generating uniform swing cast-off patterns was produced. Using artificial blood, 10 swing cast-off patterns were generated on porous paper; in each, 10 blood drops were selected for the calculation of the impact angle. Hemospat software was used for individual bloodstain analysis, and an open source code was used for estimation of area of origin. Under the same conditions, an additional 10 swing cast-off patterns were generated, and quantitative analysis was performed using trigonometric functions and an adjustment formula that minimized errors in calculating the impact angle. The adjustment formula was corrected to calculate the impact angle for the bloodstains on the porous surface. As uncertainty decreases, the error increases, and the point at which both uncertainty and error can be minimized is calculated as 75%. The existing formula included the trajectory in the estimated likelihood range in 75% of samples. When the adjustment formula was applied, the accuracy was improved, with the trajectory included in the area with a 90% likelihood. [ABSTRACT FROM AUTHOR]

• 150 mock jurors viewed bloodstain pattern analysis evidence. • Split into two groups, the test group also viewed a 3D flythrough of the scene. • The test group had significantly better knowledge retention. • There was no significant difference in emotion and confidence between the groups. 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. [ABSTRACT FROM AUTHOR]

As humanity advances into a space-faring species, the risk of injury by multiple means and intentions will follow. Expanding understanding of how forensic science adapts to extraterrestrial environments is a novel and inevitable expansion into the next forensic frontier. This study considers the unique challenges of bloodstain pattern analysis in microgravity environments. Specifically, observation in novel experimentation aboard a parabolic flight research airplane which yielded fluid dynamic behaviors in a microgravity environment that provides practical understanding of Earth-based and off-world bloodstain applications.

Objectives: This study investigated the influence of tooth position within the quadrant and method of tooth preparation on aerosol and splatter reduction by suction techniques. Materials and methods: Using four suction techniques, tooth preparation was done using fast handpiece and combined air and water spray on tooth #28, #29 and #30. Splatter, aerosol and total sound generated were recorded. Two-way analysis of variance and posthoc pairwise comparisons compared amount of aerosol, spatter and total sound among suction techniques, tooth location and method of preparation. Results: There were statistically significant more splatter (P < 0.000) for tooth preparation with air and water spray compared with high-speed handpiece for all suction techniques, but no significant difference in aerosol and total sound (P > 0.05) was recorded. A significant reduction in environmental splatter during tooth preparation of the distal tooth #30 by all suction methods was observed compared with tooth #28. However, there was no significant difference in the amount of face shield, chest, right arm and left arm splatter, aerosol and total sound based on tooth location. Overall, the prototype suction device had statistically significant less environmental splatter (P < 0.001) and aerosol (P = 0.004) than the conventional HVE device. Conclusions: The method of tooth preparation affected splatter mitigation by suction techniques but had no influence on aerosol mitigation. Mitigation of environmental splatter by suction techniques was affected by tooth position within the arch. The prototype suction device reduced environmental spatter and aerosol more than the conventional HVE device. Clinical Significance: The variations observed in aerosol and splatter mitigation based on tooth preparation methods and tooth location provides evidence for adjunctive means of reducing risk of direct transmission of infection in the dental practice such as combining strategies of protective equipment, improved room ventilation and use of air filtration system. [ABSTRACT FROM AUTHOR]

Forensic entomology is primarily focused on using carrion blow flies and beetles (Diptera and Coleoptera) to estimate the time since death. However, insect artefacts, such as footprints, defecations, regurgitations, and splatters are also considered within the disciplines of bloodstain pattern analysis (BPA), and ants (Hymenoptera: Formicidae) have been studied in forensic pathology for their potential to alter bodies. Although ant activity has been mostly reported as "dry marks" (abrasions) on decomposing bodies, their colonisation of congested or hypostatic anatomical regions can produce alterations that mimic active or recent haemorrhages. Therefore, if a body exhibits external haemorrhage/s without any apparent origin, artefacts caused by insects, such as ants, should be considered. This study describes ten cases of post-mortem ant activity observed in the Andaman and Nicobar Islands (India), and analyses the resulting external haemorrhagic artefacts, which exhibit different patterns of morphology, distribution, and location. The study proposes a classification system to aid in identifying bloodstain patterns caused by ant activity, assisting in determining the mechanism/s of the lesions, the original position of the body, and any subsequent interactions with the surrounding environment. Ultimately, this classification can improve the accuracy of reconstructing the events that occurred during the early post-mortem period, as well as the circumstances surrounding death. [ABSTRACT FROM AUTHOR]

• Case report demonstrating Bayesian reasoning in Bloodstain Pattern Analysis (BPA). • Probability assignments in an actual case are discussed. • Parameter sensitivity analysis and robustness of the likelihood ratio are discussed. • Dedicated research is needed to strengthen evaluative reporting on BPA findings. The findings from a bloodstain pattern analysis (BPA) may assist in formulating or falsifying scenarios that are considered in the investigative stages of a criminal investigation. When a case proceeds to trial the bloodstain pattern expert may be asked about the relevance of their findings given scenarios that are proposed by the prosecution and defense counsel. Such opinions provided by an expert are highly relevant to police investigation or legal proceedings, but the reasoning behind the opinion or implicit assumptions made by the expert may not be transparent. A proper framework for the evaluation of forensic findings has been developed since the late twentieth century, based on the hierarchy of propositions, Bayesian reasoning and a model for case assessment and interpretation. This framework, when implemented in casework, mitigates some of the risks of cognitive biases, and makes the reasoning and scientific basis for the opinion transparent. This framework is broadly used across forensic science disciplines. In this paper we describe its application to the field of BPA using a case example from the Netherlands Forensic Institute (NFI). [ABSTRACT FROM AUTHOR]

[Display omitted] • Impinging droplets of non-Newtonian blood and Newtonian liquid with similar viscosity on diverse wettable surfaces were comparatively investigated. • Coupling effects of liquid fluidity and surface wettability on the impact dynamics were revealed. • Key characteristics of residual stain patterns after blood drying are correlated with the impact conditions. Understanding the underlying hydrodynamics of impinging blood droplets and finding out the physical parameters determining the bloodstain characteristics are of great importance in blood related forensic investigations. In this work, the impact of non-Newtonian blood droplets on solid surfaces ranging from lyophilic to superlyophobic was systematically investigated and compared to that of Newtonian droplets with a similar dynamic shear viscosity. We show that impinging blood droplets behave as low-viscosity Newtonian droplets in the short-time spreading, which is dominated by capillary and inertial forces, but their non-Newtonian viscoelasticity would notably affect the droplet retraction and post-impact oscillation occurring in large timescales. Whereas the strong liquid–solid adhesion and the non-Newtonian elongational viscosity hinder droplet recoiling and thus alter the impact phenomena on lyophobic and superlyophobic surfaces, the shear and elongational viscosities are coupled to result in higher damping coefficients of oscillating blood droplets after deposition, in comparison to that of impinging Newtonian droplets. The size of the dried bloodstain was found to be different from both the maximum spreading radius of the droplet that can reach during impact and the final radius of the deposited droplet after oscillation, and their correlations are highly dependent on the impact velocity and surface wettability. Moreover, the morphologic characteristics of the bloodstains would also be changed by varying either the impact velocity or the surface wettability. We envision that these findings can not only find applications in the bloodstain pattern analysis, but also provide useful information for medical diagnosis based on blood droplet test. [ABSTRACT FROM AUTHOR]

Introduction: Bloodstain pattern analysis (BPA) is a crucial tool in forensic investigations, particularly in cases that involve violent crimes such as homicides, assaults, and sexual assaults. The analysis of bloodstains can provide valuable information about the location and movement of the victim and perpetrator(s), the type of weapon used, and the number and direction of the blows or shots. The lack of an objective mathematical foundation is a critical issue in a scenario where the quality of evidences can strongly affect a court trial and the life of people involved in that trial. Systematic reviews provide a rigorous and transparent method for evaluating scientific evidence, and can help to identify strengths and weaknesses of a given methodology.Methods: To ensure comprehensive retrieval of relevant research we will search the following key databases: PubMed and ScienceDirect through 1000 for peer reviewed articles (in all languages) evidence related to bloodstain pattern analysis.Discussions: This systematic review summarizes four papers that discuss different aspects of BPA. The first paper introduced the basic concepts of BPA and the use of trigonometric principles to determine the impact angle of bloodstains. The second paper presented experimental findings on the use of trigonometry in BPA and identified its limitations in determining the height of blood sprayed upwards. The third paper examined the analysis of circular bloodstains and found that their clusters can provide indirect information on impact-to-wall distance and area of origin. The fourth paper introduced the use of virtual models for BPA and found that straight-line trajectories can be used to estimate the area of origin with high accuracy.Conclusions: These papers highlight the complexity of BPA and the importance of using a combination of methods to interpret bloodstain patterns accurately. It is essential to consider the limitations of each method and to use them in combination to obtain a more complete picture of the events that occurred at a crime scene. Further research is needed to refine and improve the methods used in BPA and to develop new approaches to analyzing bloodstain patterns. [ABSTRACT FROM AUTHOR]

Given the use of modified blood products (e.g. leucocyte depleted erythrocyte concentrates in SAG-mannitol, dehydrated blood powder, defibrinated blood), drawing blood from conscious animals while minimizing their stress is a good option to obtain blood for bloodstain pattern analysis. Nevertheless, the blood must be well described since individual differences in quality can occur, and storage will influence blood components qualitatively and quantitatively. Cow has been discussed as a suitable source of blood supply, but current data lack hematological and full rheological perspectives. This project includes the respective parameters in combination with passive drip pattern experiments during refrigerated storage in multiple study arms. Cow blood displayed a constant increase in viscosity (at high shear rate: 1000s−1), reflecting the expected reduction in red blood cell (RBC) flexibility. RBCs shrank but remained intact with very few irregular shapes, therefore there was no evidence of hemolysis. Influence of storage on stain size in passive drip pattern experiments with different substrates was minimal. However in cows, it is not hemolysis but an early change in suspension properties that indicates storage lesion. Viscosity (at low shear rate: 1s−1) of some blood samples increased three-fold (peaking at day 14), transitioning sharply to near-Newtonian (almost shear-independent) behavior thereafter. The higher this increase in viscosity, the greater the increase in the number of satellite spatter on glass. In order to ensure high quality simulations in the future, comprehensive rheological analyses to detect gradual changes in blood pseudoplasticity should be implemented in the forensic discipline of bloodstain pattern analysis.

Copyright of International Journal of Legal Studies ( IJOLS ) is the property of International Institute of Innovation Science-Education-Development in Warsaw and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An improved automated bloodstain pattern analysis method has been developed and validated, which utilises computer vision techniques to identify bloodstains on a plain background within a digital image. The method generates metrics relating to the individual stains as well as the overall pattern, including bloodstain pattern specific metrics such as the gamma angle, circularity, solidity, area of convergence, stain density and pattern linearity. This method provides an objective approach to the analysis of bloodstains and bloodstain patterns and can generate a wealth of quantitative data that is currently not obtainable using manual techniques or other image-based programs currently utilised in the discipline. This method will be useful to analysts and researchers investigating the application of quantitative methods to bloodstain pattern analysis. • A method that automatically analyses digital images of bloodstain spatter patterns is described. • Improved stain segmentation detects even very small stains under varied lighting conditions. • A novel approach to fitting ellipses allows for accurate BPA specific metrics to be calculated. • Quantitative data is quickly and reliably extracted from patterns increasing objectivity. [ABSTRACT FROM AUTHOR]

The female victim died 17 h after the discharge of a.38 caliber unjacketed bullet into the temporal bone above her right ear. Her boyfriend was accused of homicide and convicted. The victim was able to affect coordinated movements for some seconds after her devastating head wound. Her post shooting movements were documented by bloodstains. Two forensic pathologists where mistaken in calling gunpowder stippling on the victim’s scalp as suture punctate wounds. The ruptured right meningeal artery was spurting. Blowback spatter transitioned into the arterial spurting spatter as the victim fell to the floor. The post-shooting movements of the victim created stains that confused two bloodstain experts who believed the victim could not move after her cranial wounding. The victim’s hair sample, taken by the emergency room doctor, lacked chain and was subsampled by an unknown party prior to chemical gunshot residue (GSR) testing. The tests were negative which led to the erroneous conclusion the shot was from a distance. The mishandling of the hair sample was not discovered until after trial. A GSR expert testified that the airborne GSR settles in seconds in an enclosed area. However, later publications concluded GSR remains airborne for many minutes. The GSR contamination of the defendant was instrumental in his conviction. The GSR expert never informed the DA or the Court of his error. The evidence indicates the victim’s gunshot wound was self inflicted.

Two men were wrongfully convicted of murder in 2017 and sentenced to life imprisonment. After a physical altercation inside a flat, the victim (A) was found dead approximately 60 m away outside a residential address. He had sustained a number of injuries including a stab wound to the left side of his neck which was found to have divided the right carotid artery. The location where A was found was not regarded as a crime scene and not subjected to a specialist forensic examination by scientists as it was assumed that the fatal injury was sustained in the flat. The pathologist, who subsequently carried out the autopsy on A, was not asked to attend the scene. A review of the blood distribution at the scene in conjunction with the pathology findings indicated however that the fatal neck wound had been inflicted outside the flat, near to where the victim was found. An appeal against the convictions for murder was upheld in 2021 and a re-trial ordered. Following this second trial, both accused were acquitted of murder and released from custody. The new pathology and blood pattern evidence introduced at the second trial was a major part of the defense strategy which led to the acquittal of the accused. The case illustrates that a more inclusive and detailed crime scene strategy had been undertaken, including an assessment of the bloodstains present, in conjunction with discussion with the pathologist, then the likelihood is that the two men subsequently charged with murder would have been eliminated as suspects and a miscarriage of justice would have been avoided. [ABSTRACT FROM AUTHOR]

The differentiation between bloodstain patterns resulting from impact events and those from the expiration of blood can be crucial to crime scene reconstruction. Physical characteristics used to distinguish impact and expirated bloodstain patterns, are often unclear or absent, making interpretation of some bloodstain patterns difficult. Presumptive tests for salivary α-amylase (SAA) exist; however, these tests are generally unsuited for use at crime scenes or have not been tested on realistic expirated bloodstains. To address this, we assessed the RSIDTM-Saliva test for detecting SAA in expirated bloodstains and developed a modified protocol that can be used in-scene by forensic examiners. Phase 1 experiments, which involved volunteers creating simulated bloodstains by expirating volumes of their own blood onto painted timber boards, produced entirely positive results which demonstrated the test's efficacy for realistic expirated bloodstains. Phase 2 development and evaluation of a modified in-scene protocol demonstrated that a reduced buffer volume and modified incubation could successfully detect SAA in expirated bloodstains. A significant inverse relationship was observed between the size of a bloodstain and the 'time-to-positive'. These results support the modified RSIDTM-Saliva test protocol as a viable method to detect SAA in expirated bloodstains in a crime scene environment. [ABSTRACT FROM AUTHOR]

Bloodstain pattern analysis plays a crucial role in forensic investigations. Projected patterns can offer valuable insights into the dynamics of crime scenes. In this paper, we propose and validate a novel approach that extends existing software, HemoVision, to analyze impact patterns that are distributed across multiple arbitrarily oriented surfaces. The proposed method integrates HemoVision's marker-based system with structure from motion (SfM) techniques to reconstruct the three-dimensional geometry of impact patterns using only two-dimensional photographs. Controlled experiments were used to validate the proposed approach, demonstrating robustness in reconstruction accuracy with median translation errors below 3 mm and median angular errors below 0.2°, irrespective of imaging device or image resolution. Comparing the estimated areas origin to their known ground truth, the proposed method achieved an average total error of 8.12 cm, with the primary source of error being the vertical dimension. Despite this, the overall error remains well within the ranges of error reported in prior work. This study demonstrates that HemoVision can be used to analyze complex impact patterns using only two-dimensional photographs, providing forensic experts with an efficient and accessible tool for investigating intricate crime scenes involving multi-surface impact patterns. • HemoVision is extended with photogrammetry to create 3D scenes from 2D photographs. • Impact patterns were created in controlled experiments for validation. • 3D reconstructions had median translation and rotation errors of 3 mm and 0.18°. • Resulting area of origin estimates had a mean total error of 8.12 cm. • HemoVision is an efficient and accurate tool for analyzing complex impact patterns. [ABSTRACT FROM AUTHOR]

Bloodstain pattern analysis (BPA) on absorbent surfaces, such as fabrics, is far more complex compared to its application on smooth, hard, non-porous surfaces. Angle of impact and directionality are commonly interpreted from bloodstains but may be adversely affected by porous surfaces. In fact, there is a lack of evidence that traditional approaches to BPA are even applicable when blood impacts absorbent materials such as clothing and other fabrics. Hence, there is a critical need for research focusing on the validity and reliability of methods for bloodstain pattern analysis on textiles. Here, human blood drops were deposited on six different fabric types (cotton, satin polyester, rayon, blended polyester/spandex, blended nylon/spandex, and blended modal/polyester/spandex) at two known impact angles: 30° and 10°. Bloodstain morphology was found to be unique for each fabric. Calculated angles of impact for cotton and satin polyester were not statistically different from the known angle of impact while blended polyester/spandex, blended nylon/spandex, and blended modal/polyester/spandex significantly underestimated the known angle of impact. Even when stain morphology on fabric resembled those on a glass control, the angle of impact significantly underestimated the known. The ability to assign directionality based upon bloodstain morphology was dependent on the fabric type. These findings support the need for further research and the development of guidelines for bloodstain pattern interpretation on fabric materials. • Bloodstain area on some fabrics was smaller than glass despite evidence of wicking. • Impact angle varied with wicking and fabric thickness, roughness, and construction. • Known and estimated impact angles were consistent for cotton, polyester, and rayon. • On single knit fabrics, the known impact angle was underestimated. • The ability to assign directionality was dependent on the fabric type. [ABSTRACT FROM AUTHOR]

The ability to accurately detect bloodstains is fundamental to crime scene examination; however, traditional methods can be inadequate for use on many dark-coloured surfaces commonly encountered at scenes, such as fabrics and flooring. An alternative approach may be the use of infrared (IR) photography, which is known to be effective at detecting bloodstains on fabrics and some non-porous surfaces. However, a knowledge gap exists concerning the effectiveness of IR photography for detecting bloodstains on dark-coloured floor coverings. To address this, we used a paired sampling design to assess the performance of IR photography compared with tetramethylbenzidine (TMB) and luminol for detecting bloodstains on wool and nylon carpet, linoleum, vinyl, tile and laminate flooring. We also assessed whether IR imaging would detect a substance known to create false-positive reactions with TMB and luminol. Overall, our results supported IR photography as an effective, non-destructive method compared to TMB and luminol for detecting bloodstains on dark-coloured flooring, especially nylon carpet, tile, laminate and vinyl. Further, IR did not detect known false-positive samples on several surfaces. This research contributes to a growing body of literature concerning the forensic applications of IR photography and has significant operational implications for crime scene examiners. [ABSTRACT FROM AUTHOR]

Insects found at a crime scene can produce traces referred to as fly artifacts (FA) due to their movement over the corpse and the manner in which they feed upon it. These can be detrimental for carrying out criminal investigations. Confusing a FA with a genuine bloodspot can lead to misinterpretations, also taking into consideration that FA may contain a human DNA profile. The aim of the present study was to employ scanning electron microscopy (SEM) for the analysis of FA produced by Calliphora vomitoria on hard surfaces and fabrics that are commonly present at crime scenes. FA and control bloodstains were produced under experimental conditions on metal, glass, plaster, cotton, and polyester. After macroscopic analysis, FA were examined at standard low (20–40 ×), medium low (300–600 ×), and high ultrastructural (1200 ×) magnification through a SEM Stereoscan 360, Leica, Cambridge. SEM analysis enabled the identification of distinctive features of FA on hard surfaces, namely, amorphous crystals, micro-crystals with a morphology similar to those of uric or micro-crystals with a comparable morphology to cholesterol, absent in controls. Moreover, red blood cells (RBC) were absent in FA but were always present in controls. On cotton, for both FA and controls, the drop was almost completely absorbed and thus indistinguishable from the underlying fabric texture. On polyester, FA showed amorphous/crystal-like deposits and no RBC, as observed on hard surfaces, except for those showing a completely flat surface. SEM analysis appeared to be suitable for differential diagnosis between FA and genuine bloodstains on hard surfaces, although the results may be inconclusive on tested fabrics. [ABSTRACT FROM AUTHOR]

There is an apparent paradox that the likelihood ratio (LR) approach is an appropriate measure of the weight of evidence when forensic findings have to be evaluated in court, while it is typically not used by bloodstain pattern analysis (BPA) experts. This commentary evaluates how the scope and methods of BPA relate to several types of evaluative propositions and methods to which LRs are applicable. As a result of this evaluation, we show how specificities in scope (BPA being about activities rather than source identification), gaps in the underlying science base, and the reliance on a wide range of methods render the use of LRs in BPA more complex than in some other forensic disciplines. Three directions are identified for BPA research and training, which would facilitate and widen the use of LRs: research in the underlying physics; the development of a culture of data sharing; and the development of training material on the required statistical background. An example of how recent fluid dynamics research in BPA can lead to the use of LR is provided. We conclude that an LR framework is fully applicable to BPA, provided methodic efforts and significant developments occur along the three outlined directions. [ABSTRACT FROM AUTHOR]

Copyright of Criminalistic Theory & Practice / Kriminalistička Teorija & Praksa is the property of International Criminalistic Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents the assumptions of bloodstain pattern analysis as forensic science. Thanks to its application, it is possible to carry out better DNA genetic research, aiming to reconstruct the event. The article is based on literature research, the study of criminal case files and the author's personal experience as an expert witness. The paper aims to create a scientific discussion about the proper documentation and prioritisation of blood traces for genetic testing. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Legal Studies ( IJOLS ) is the property of International Institute of Innovation Science-Education-Development in Warsaw and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fly artifacts resulting from insect activity could act as confounding factors on a crime scene and interfere with bloodstain pattern analysis interpretation. Several techniques have been proposed to distinguish fly artifacts from human bloodstains based on morphological approach and immunological assay, but a DNA-based method has not been developed so far. Even if in forensic genetic investigations the detection of human DNA is generally the primary goal, fly artifacts can provide useful information on the dynamics of crime events. The present study provides a molecular method to detect fly DNA from artifacts deposited by Calliphora vomitoria after feeding on human blood through the analysis of the mitochondrial cytochrome oxidase gene subunit I (COI). Fly artifacts originated from digestive process and of different morphology spanning from red and brownish/light brown, circular and elliptical stains to artifacts with sperm-like tail or a tear-shaped body were collected. The COI amplification was successfully obtained in 94% of fly artifact samples. The method showed high sensitivity and reproducibility, and no human DNA contamination was observed, offering specificity for use in confirmatory test. This molecular approach permits the distinction of fly artifacts from genuine bloodstains and the identification of fly's species through the COI region sequencing by protocols usually applied in forensic genetic laboratories. [ABSTRACT FROM AUTHOR]

The first point of contact between a spherical blood drop and a surface is related to the angle between the trajectory of the blood drop and the surface being struck. This angle is often referred to as the impact angle which can be estimated by knowing the width and length of the resultant elliptical bloodstain. Most software programs dedicated to area of origin analysis indicate the location of the backtracked bloodstain trajectory to be at the geometric centre or at the tip of the bloodstain ellipse. However, it is unknown how the first point of contact and the blood drop trajectory (here defined as the locus of the centre of mass of the drop as it travels) are related empirically. Thus, this study aims to look at how the initial point of contact and the trajectory at the impact of a blood drop relates to the formed bloodstain ellipse. Two volumes of blood (0.013 ml and 0.071 ml) were dropped from a height of 10 cm and 40 cm onto an inclined surface at 0°, 15°, 30°, 45°, 60°, and 75°. The transition from a spherical blood drop to an elliptically shaped bloodstain was recorded using a high-speed camera for all tests. A total of 72 ellipses were analyzed to determine the location of the first point of contact and trajectory point of the blood drop and how they relate to the formed elliptical bloodstain. A relationship was found between the first point of contact and the bloodstain trajectory which was dependent on the impact angle. However, there were clear deviations from theoretical assumptions due to blood drop oscillations, the effects of gravity, and the natural fluid characteristics of blood. The results of this study may assist bloodstain pattern analysts and software developers by more accurately applying the location of the blood drop trajectory based on empirical data. • The first point of contact follows a similar trend to the sine value. • The trajectory point moves along the half-length of the bloodstain. • The trajectory point and first point of contact are mainly at different locations. • The trajectory point is not always at the centre or tip of the ellipse. • The first point of contact is not always at the centre of tip of the ellipse. [ABSTRACT FROM AUTHOR]

• 21 Bloodstain pattern analysts examined 6 self-selected prepared stain patterns. • They calculated the AO which was compared with FARO 3D software performance. • The maximum error for any one impact analysis was identified as 24.27 cm deviation. • An absolute average error rate of 5.62 cm was established. • None of the values exceeded the 30 cm acceptable allowance. 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. [ABSTRACT FROM AUTHOR]

• Whole bovine blood with ACD-A anticoagulant is an appropriate blood source for basic BPA research. • This blood source with ACD-A can be stored in ambient conditions. • The concentration volume of ACD-A anticoagulant added influences fluid properties. • DFF Fluid properties change predictably over time similarly to previous research. Mammalian whole blood sources are often used for forensic research and training when human samples cannot be sourced. While porcine, ovine and equine blood have been shown to be viable alternatives to whole human blood for forensic purposes, procurement can still pose a problem, especially for smaller and remote institutions. This work explores the use of whole bovine blood for basic bloodstain simulation. Sample preparation through the addition of ACD-A anticoagulant was optimized and storability was explored. Viscosity, surface tension, density, and packed cell volume, four fluid properties relevant to bloodstain pattern analysis, were monitored over four days and in two temperature conditions. Linear mixed models accounting for variation in the donor demonstrated that these fluid properties of the bovine blood changed predictably over time and with temperature. Whole bovine blood with 12.5% v/v ACD-A was found to be viable for use in basic bloodstain simulation at ambient and physiological temperature. [ABSTRACT FROM AUTHOR]

For investigative purposes, the bloodstain pattern analyst might have to estimate whether a given stain on fabric could have originated from a specific location. A wide range of values of the maximum distance that a blood drop can travel have been reported based on experiments, ranging from less than 1 m to more than 10 m. It is also known that stains on porous materials such as fabrics are more difficult to interpret than stains on non-absorbing surfaces, because of wicking. Here, we perform several fluid dynamic spatter experiments and formulate a fluid dynamics model to describe the trajectories of the blood drops. The experiments are performed with swine blood, the properties of which are well understood. The main parameters screened are the drop size, initial velocity, the launch angle, and the orientation of the fabric. A large number of blood drops are produced by impact events. The resulting stains on knitted white T-shirt fabric are digitally measured. Their position relative to the source and size is reported. Trajectories are simulated accounting for the influence of gravity and drag forces. A simple relation between drop size and stain size is established based on extensive experiments on a specific fabric. Results of the trajectory simulations are then searched and mined for parameters directly measurable on a crime scene, such as the stain size on fabric and the relative location of the fabric with respect to the blood source. The experimental results are compared and found in agreement with the numerical predictions. The results are presented in one chart relevant to crime scene reconstruction. The chart is easy to use and only requires minimum knowledge of fluid dynamics. [ABSTRACT FROM AUTHOR]

Argument: In the United States, scientific knowledge is brought before the courts by way of testimony – the testimony of scientific experts. We argue that this expertise is best understood first as related to the quality of the underlying science and then in terms of who delivers it. Bloodstain pattern analysis (BPA), a contemporary forensic science, serves as the vaulting point for our exploration of objectivity as a metric for the quality of a science in judicial contexts. We argue that BPA fails to meet the minimal standard set by Helen Longino's social-procedural account of objectivity (1990, 2002). In light of some pressing issues for social-procedural accounts, we offer an infrastructural account of objectivity. This account offers what amounts to a friendly amendment to Longino's account and adds to the ways in which we might analyze social-procedural objectivity. Finally, we address an issue that is pressing in the legal context: given that scientific knowledge is delivered by individuals, not communities, at least in U.S. courts, we (may) need a way to evaluate individual scientific and epistemic agents. We suggest a means for making this evaluation that is derived from our infrastructural account of objectivity. [ABSTRACT FROM AUTHOR]

In bloodstain pattern analysis (BPA), a field of forensic science, there has been active discussion on the estimation of the area of origin of impact spatter. However, there is no established methodology to quantitatively analyze the area of origin of a swing cast-off pattern. To quantitatively analyze the methodology of previous research on estimation of area of origin, a device for generating uniform swing cast-off patterns was produced. Using artificial blood, 10 swing cast-off patterns were generated on porous paper; in each, 10 blood drops were selected for the calculation of the impact angle. Hemospat software was used for individual bloodstain analysis, and an open source code was used for estimation of area of origin. Under the same conditions, an additional 10 swing cast-off patterns were generated, and quantitative analysis was performed using trigonometric functions and an adjustment formula that minimized errors in calculating the impact angle. The adjustment formula was corrected to calculate the impact angle for the bloodstains on the porous surface. As uncertainty decreases, the error increases, and the point at which both uncertainty and error can be minimized is calculated as 75%. The existing formula included the trajectory in the estimated likelihood range in 75% of samples. When the adjustment formula was applied, the accuracy was improved, with the trajectory included in the area with a 90% likelihood., (© 2024 The Authors. Journal of Forensic Sciences published by Wiley Periodicals LLC on behalf of American Academy of Forensic Sciences.)

Forensic investigation has the primary challenge of assessing cause from limited evidence. The use of computational modelling can play a role in assessing potential ballistic pathways in a crime investigation by analysing; (a) the entry wound and blood spatter patterns; (b) the influence of target materials; and (c) the cranial geometry, to inform the investigation process. In particular, the retrograde ejection of blood and tissue from the entry wound following projectile impact, called 'backspatter', and can help inform the proximity of the shooter and potentially differentiate between suicide and homicide, while providing other important forensic information. However, the 'backspatter' phenomenon is not well understood due to the lack of viable surrogate models and the difficulties of analysing the high-speed, extreme-force impact. This study presents (i) the development of an anatomically based model of cranial ballistic injury using the Smoothed Particle Hydrodynamics (SPH) method; (ii) the simulation of the tail splashing and temporary cavitation mechanisms and the effect of different cranial skin and cranium simulants on backspatter generation; (iii) an evaluation of anatomical geometry simulation results such as stress and strain and velocity of the particles ejected as backspatter; and (iv) a parametric study of the effect of bullet calibre and speed on the ballistic response of the anatomical geometry computational model. [ABSTRACT FROM AUTHOR]

Cast‐off stains are common patterns found at crime scenes involving blood shedding events. However, the analysis and interpretation of cast‐off patterns remains an area lacking tools for crime scene investigators. Analyzing cast‐off patterns may allow investigators to interpret the area from where an object may have been swung and thus determine the approximate location of a suspect or victim. This study looked at the position and distribution of cast‐off patterns and area of origin as a starting point for the development of a method to analyze cast‐off patterns. Through a series of tests using a controlled cast‐off rig (n = 10), it was observed that a Path Volume Envelope (PVE) may be identified where the swinging path is contained in a volume along with an area of exclusion. The calculated center, linear position of the PVE was found to have an average error of just over 3.2 cm when compared to the known object swing path position. The maximum deviation of the PVE to the known swing path was found to be 5.0 cm with a standard deviation of 1.4 cm. Additional studies are required to investigate the effects of partial cast‐off stains, wielded object velocity, direction of swing, distance from the projected surface, and other factors. The observations and analysis from this study were seen to be predictable and repeatable and may provide a possible new method for investigators to interpret cast‐off stains. [ABSTRACT FROM AUTHOR]

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Courtrooms are asking for reliable scientific evidence in order to prevent wrongful convictions. Thus, a more rigorous approach to forensic science approved by scientific methods is promoted. The study of human blood dynamics in the context of forensic science is becoming a widespread research topic, although the physics behind wetting and drying of blood is not completely understood. Based on the morphological changes of drying blood pools, the following work presents a patentable method to quantitatively date these blood pools for forensic purposes. As for drying drops of blood, cracking patterns are observed but they are more disordered. Similar disordered crack patterns are observed in the case of gels, their evaporation process is, therefore, presented since this topic has been thoroughly investigated. We aim to find reliable patterns that could give information concerning the evolution of a blood pool over time to lead to practical application of this knowledge. An empirical model is established between final dried blood patterns and the generating mechanism, yielding application in bloodstain pattern analysis for forensic investigations. [ABSTRACT FROM AUTHOR]

The forensics discipline of bloodstain pattern analysis plays an important role in crime scene analysis and reconstruction. One reconstruction question is whether the blood has been spattered via gunshot or blunt impact such as beating or stabbing. This paper proposes an automated framework to classify bloodstain spatter patterns generated under controlled conditions into either gunshot or blunt impact classes. Classification is performed using machine learning. The study is performed with 94 blood spatter patterns which are available as public data sets, designs a set of features with possible relevance to classification, and uses the random forests method to rank the most useful features and perform classification. The study shows that classification accuracy decreases with the increasing distance between the target surface collecting the stains and the blood source. Based on the data set used in this study, the model achieves 99% accuracy in classifying spatter patterns at distances of 30 cm, 93% accuracy at distances of 60 cm, and 86% accuracy at distances of 120 cm. Results with 10 additional backspatter patterns also show that the presence of muzzle gases can reduce classification accuracy. [ABSTRACT FROM AUTHOR]

Bloodstain pattern analysis has a key role in crime scene reconstruction; however, it can be hampered by diverse confounding factors, such as insect activity which may lead to the production of small artifactual bloodstains, commonly referred to as fly artifacts (FA). Although several techniques aimed at distinguishing human bloodstains and FA have been developed, actually, no standardized and reproducible methodology is available. The aim of our study was to test the use of scanning electron microscopy (SEM) to distinguish human bloodstains from FA produced by Sarcophaga carnaria. FA and bloodstains have been produced on five different deposition surfaces under experimental conditions. After visual analysis, bloodstains and FA were analyzed at standard low (× 40–× 300) and high (× 600–× 1200) magnification through a Philips SEM 515. Although differential diagnosis between bloodstains and FA resulted often inconclusive at visual analysis, SEM analysis allowed the identification of additional key distinctive morphological features. In particular, on the surface of FA, small crystal-like and/or amorphous material deposits were observed. Such deposits were absent on bloodstains which, on the other hand, displayed red blood cells stacked in "rouleaux." Basing on these results and under our experimental conditions, SEM analysis resulted suitable to perform a differential diagnosis between bloodstains and FA produced from the insect activity of Sarcophaga carnaria. [ABSTRACT FROM AUTHOR]

This comparative study aimed to investigate the differences between the workflow, accuracy, and reproducibility of the area of origin tools in FARO Scene and FARO Zone 3D software. Released in 2018, FZ3D has recently been introduced as an alternative application to FARO Scene's Forensic Wizard plug-in for bloodstain pattern analysis but no accuracy studies have been published at the time of this study. A total of 15 impacts were created using an impact rig at three different positions from two orthogonal walls (50cm, 75cm, 100cm). One researcher conducted the analyses with both software packages, and the total errors using FZ3D were not statistically greater than using FARO Scene (p>0.05). With FZ3D, 50% of the total errors ranged from 6.63cm to 15.68cm with a minimum of 2.45cm, maximum of 27cm, and median of 11.22cm. With FARO Scene, 50% of the total errors ranged from 3.6cm to 15.5cm with a minimum of 2.93cm, maximum of 31.25cm and median of 9.6cm. A blind test with seven participants analyzing the same 15 impacts in FZ3D resulted in 100 out of 105 total errors (95%) to be within the accepted error range of 20cm. Of the five total errors outside 20cm, one was obtained from the 75cm position and four from the 100cm position. 75% of the total errors were below 9.43cm from the 50cm position, 14.88cm from the 75cm position, and 17.39cm from the 100cm position. This could indicate that there is a positive correlation between the distance of the impact from the surfaces and total errors obtained. Based on results of previous literature and comparison to FARO Scene software, FZ3D is shown to have acceptable area of origin analysis tools. [ABSTRACT FROM AUTHOR]

The determination of the role that drugs may have played in a death is an important part of the investigation into unexplained deaths. Renal impairment may lead to a reduction in drug excretion rate and therefore an accumulation of drugs or metabolites, leading to possible toxic or lethal effects. Creatinine levels are known to be stable in the post mortem period and in life can give an indication of kidney function. There are however widely reported limitations when using creatinine in isolation and so we investigated the usefulness of using estimated glomerular filtration rate (eGFR) for scoring an individual as having renal impairment using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. We analysed unpreserved vitreous for creatinine in 812 individuals using an isotope dilution mass spectrometry (ID-MS) traceable enzymatic. We found that the biochemical analysis of post mortem vitreous creatinine and subsequent calculation of eGFR is a useful adjunct to the standard testing that takes place during a post-mortem examination and can assist in death investigation. Using an eGFR of <60 mL/min/1.73 m2 gave a sensitivity of 94.3% and specificity of 97.3% when scoring an individual as having renal impairment. We therefore recommend the calculation of eGFR for the determination of possible renal impairment in post mortem investigations. It is, of course, always pertinent to interpret any results using a wealth of case information. Extreme caution should be exercised in cases where insufficient clinical information/history is available, particularly in cases in which there is suspected diabetic ketoacidosis, dehydration or hospitalisation prior to death. [ABSTRACT FROM AUTHOR]