Bloodstain Pattern Research Articles

Impinging blood droplets on different wettable surfaces: Impact phenomena, contact line motion, post-impact oscillation and dried stains

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.

Optical profilometry for forensic bloodstain imaging.

Understanding the physical, chemical and biological changes that occur during the drying of a bloodstain is important in many aspects of forensic science including bloodstain pattern analysis and time since deposition estimation. This research assesses the use of optical profilometry to analyze changes in the surface morphology of degrading bloodstains created using three different volumes (4, 11, and 20 μL) up to 4 weeks after deposition. We analyzed six surface characteristics, including surface average roughness, kurtosis, skewness, maximum height, number of cracks and pits, and height distributions from the topographical scans obtained from bloodstains. Full and partial optical profiles were obtained to examine long-term (minimum of 1.5-h intervals) and short-term (5-min intervals) changes. The majority of the changes in surface characteristics occurred within the first 35 min after bloodstain deposition, in agreement with current research in bloodstain drying. Optical profilometry is a nondestructive and efficient method to obtain surface profiles of bloodstains, and can be integrated easily into additional research workflows including but not limited to time since deposition estimation. Optical profilometry is a non-contact tool to scan bloodstains in ambient conditions Drying phases are observable in small drip bloodstains Significant surface morphology changes occur within 35 min after deposition.

Cow blood – A superior storage option in forensics?

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.

Some experiments and remarks regarding the possible formation of blood stains on the Turin Shroud: stains attributed to the crown of thorns, the lance wound and the belt of blood.

The Turin Shroud (TS) is a Christian relic interpreted to be the burial cloth of Jesus of Nazareth. It exhibits red discolorations that have been interpreted as blood stains and that are the subjects of a highly controversial discussion. We conducted experiments to identify theoretically possible explanations for the stains attributed to the crown of thorns, the lance wound and the belt of blood.In the experiments with a focus on the stains attributed to the crown of thorns, a very similar stain pattern as on the TS could be provoked by simulating the following sequence of events: blood from antemortem scalp wounds is covering hair and face; blood is coagulating and/or drying; blood components are mobilised by postmortem washing and oiling.A stain pattern very similar to the belt of blood on the TS was successfully provoked by simulating the following sequence of events: The body is lying in a supine position, blood or bloodied water flowing from a wound at the right lateral chest wall; the body is rotated to the left side; the Shroud is tucked under the back; the body is rotated back to a supine position and laid onto the Shroud. The so-called serum ring surrounding the stain attributed to the lance wound could be reproduced by sequential application of serum and whole blood samples or of pleural effusion and whole blood samples onto cotton cloth.It is obvious that any attempt to interpret the assumed blood stain pattern on the TS has serious limitations. Nevertheless, it seems remarkable that we were able to reproduce findings that appear to be very similar to stains on the TS.

The Quixotic Quest for Objectivity in Observation

The Quixotic Quest for Objectivity in Observation

Mapping homicide by 3-D modelling of bloodstain patterns at crime scene.

Three-dimensional (3-D) modelling can be a useful technical aid and we used it to reconstruct a homicide scene to corroborate the statement of an eyewitness. 3-D modelling of the bloodstain was conducted by Micro Smith Poser 11 and Autodesk 3-Ds Max software. The technique was found to be easily understandable by the police and judiciary in the interpretation of the sequence of the events of the crime. It refuted the eye-witness's account of the actions of the accused who was charged with murder and allowed collection, storage and retrieval of the patho-anatomic information about the deceased. The checks on the accuracy of statements given by eye-witnesses that can be provided by 3-D modelling may change the outcome of criminal investigations in future.

A Fatal Suicidal Knife-Cuttings on the Neck-From an Evidence Based Forensic Pathologist’s Point of View

A 42-year-old male was found dead inside his small trunk lying on the right back seat in a pool of blood by his father. A large single-edged utility knife was discovered on right hand of the back car seat nearby. On his neck, there were four sharp hesitate incisional cuts and two hesitate incisional cuts on his left forearm. The forensic bloodstain pattern compatible with possible to hypothesize a carotid artery injury of high-pressure blood exiting from a severed artery. One of four hesitated incisions on hist neck was deep enough to sever right common carotid artery and internal jugular vein. Death was attributed to hemorrhagic shock following right carotid artery severed injury on the neck. A suicide note was found at home by his father and disclosed a combined couple and financial relationship issue. From an evidence-based forensic pathological viewpoint, at first, a clean, detailed visual observation of the cut wounds on his neck and right forearm was a key feature of differential diagnosis of cause of death. Local inspection of incised depth and damaged great blood vessels on his neck, associated with other self-inflicted wounds on his accessible parts of left forearm. The blood spatter marks analysis could determine the dynamic mechanism of bleeding to death. Based on combined circumstantial evidence, terminal individual behavior and police and legal investigation of motivation and personality, the manner of death whether in nature of suicide or homicide or not would be determined. Furthermore, a complete, integrated medicolegal investigation was the milestone of evidence-based forensic pathology to elucidate the fact of death in modern forensics. For understand the individual's background disease for tendency of suicide and/or influenced of alcohol or abuse drug could be confirmed by performed autopsy findings and toxicological analysis.

Alginate/xanthan gum hydrogels as forensic blood substitutes for bloodstain formation and analysis.

Understanding the behaviour of human blood outside of the body has important implications in forensic research, especially related to bloodstain pattern analysis (BPA). The design of forensic blood substitutes (FBSs) can provide many advantages, including the incorporation of multiple physiological components for use as safe and reliable materials for forensic applications. In this work, we present the design of synthetic alginate and xanthan gum-based hydrogels that contain electrosprayed microparticles (MPs) with and without crosslinked DNA. In addition to the MPs, the alginate/xanthan gum FBS materials include fillers to alter the physical appearance and fluid properties of the material. The optimized FBS consisted of alginate (1% w/v) and xanthan gum (5.0 × 10-3% w/v), 2 mM CaCl2, ferric citrate (0.5% w/v), magnesium silicate (0.25% w/v), Allura Red dye (2% w/v), 0.025% v/v Tween 20 and 9.5% v/v MPs. The FBS was tested in passive dripping experiments relevant to BPA scenarios at various impact angles. The spreading ratio (Ds/D0) was determined for 90° stains made on a paper surface and compared to bovine blood where the FBS was shown to simulate accurate and predictable spreading behaviour. In addition, we simulated other common BPA scenarios (e.g., impact patterns) and evidence processing potential. The FBS could be swabbed, and the DNA could be extracted, amplified, and genotyped analogous to human blood evidence. A stability test was also conducted which revealed a shelf-life of over 4 weeks where the material remains relevant to human blood at physiological temperature.

Identity of the numerous bloodstains at the murder scene: molecular identification of fly artifacts and fly species by CO1 analysis.

Crime scenes may contain insect artifacts as well as samples of human origin. While the presence of insects can be important evidence in forensic medicine and forensic entomology, the insect artifacts sometimes interfere with the interpretation of bloodstain pattern analysis (BPA) which can be critical for accurate crime reconstruction. Fly artifacts are especially complicated to distinguish from true bloodstains. Indeed, we encountered a murder scene with numerous bloodstains inconsistent with the cause of death and had trouble interpreting them. The morphological method has been developed to distinguish them, but this method has to rely on the analyst's experience and opinion. This study aims not only to distinguish fly artifacts from true bloodstains but also to identify fly species by detecting fly DNA in small amounts of bloodstains at the scenes. Melt curve analysis of real-time PCR (qPCR) targeting cytochrome c oxidase subunit 1 (CO1) of mitochondrial DNA (mtDNA) was able to detect fly DNA in bloodstains from a murder scene. The fly DNA was sequenced from the qPCR product, and the fly species were identified by BLAST search. Fluorescence-labeled specific primers for four species of necrophagous flies were designed based on the sequences of the CO1 region, and differences in the length of the amplification products were used to identify fly species from trace amounts of fly DNA in the artifacts.

Towards a likelihood ratio approach for bloodstain pattern analysis

In this work, we explore the application of likelihood ratio as a forensic evidence assessment tool to evaluate the causal mechanism of a bloodstain pattern. It is assumed that there are two competing hypotheses regarding the cause of a bloodstain pattern. The bloodstain patterns are represented as a collection of ellipses with each ellipse characterized by its location, size and orientation. Quantitative measures and features are derived to summarize key aspects of the patterns. A bivariate Gaussian model is chosen to estimate the distribution of features under a given hypothesis and thus approximate the likelihood of a pattern. Published data with 59 impact patterns and 55 gunshot patterns is used to train and evaluate the model. Results demonstrate the feasibility of the likelihood ratio approach for bloodstain pattern analysis. The results also hint at some of the challenges that need to be addressed for future use of the likelihood ratio approach for bloodstain pattern analysis.

Quantifying forensic investigations involving bloodstain pattern analysis within the UK

Research informed by practice is more likely to have a greater impact on society. However, forensic cases are confidential and thus, real-life data regarding the details of violent crime is usually withheld from the public and academia. Through a partnership between the authors institution and a UK police service, casefiles from 78 criminal investigations from 2012 to 2020 involving Bloodstain Pattern Analysis (BPA) were examined and quantified. The most common methods of assault and weapons used were identified as well as the frequency of different bloodstain pattern classifications. The results of this study will help inform researchers and supply forensic training providers with data derived from forensic practice. Despite a significant body of literature exploring impact patterns and software for calculating the Area of Origin (AO), impact pattern was classified at only 22% of scenes, with sharp-force trauma being the most prevalent form of assault. This paper recommends a review of the BPA terminology, to include additional commonly encountered patterns that are not defined by the current standard.

Evaluation of digital panoramic images to support off-site bloodstain pattern analysis

ABSTRACT Crime scene photography plays a fundamental role in forensic investigations. Its primary purpose is the recording of the entire crime scene, both the context and specific details, for later recollection, analysis and presentation. Bloodstain pattern analysis (BPA) relies extensively on the recording of context and detail. This study evaluated the use of panoramic imaging for the recording of impact patterns at crime scenes to support the off-site determination of area of origin (AO). This evaluation used a commercially available hardware system that consisted of a robotized, tripod-mounted platform, interfaced with a digital camera, to provide an automated panoramic image capture process. Software was subsequently used to construct a digital panorama. Bloodstain pattern analysis software was then used for the off-site determination of AO from the panoramic image. The results of this research demonstrated that the developed method can be employed to effectively capture a panoramic image of an impact pattern with sufficient detail for accurate AO determination. The approach can enable crime scene officers to record impact patterns without extensive training on BPA or the recording of blood spatter. The approach also enables BPA experts to digitally analyse spatter information from a single image as opposed to evaluating multiple photographs.

Self-inflicted hammer blows to the head—Literature and case review

Self-inflicted hammer blows to the head are rare occurrences in forensic medicine, particularly when they are lethal. In the majority of cases, no distinction between self-inflicted injury versus assault has to be made. However, when assault is claimed and such distinction is required, the task may be challenging.We report a case concerning a 32-year-old psychotic woman, who had suffered multiple lacerations of the scalp and survived after claiming she had been assaulted with a hammer by an acquaintance. A clinical forensic examination was performed as well as the inspection of the scene of the incident for bloodstain pattern analysis. In summary, findings were inconsistent with assault and the injuries were determined to be self-inflicted.In addition, a retrospective analysis of our own autopsy records as well as a search in scientific literature and the internet for self-inflicted hammer blows to the head was conducted. For the majority of published cases a positive psychiatric history is reported. While published cases were few, potentially characteristic properties of self-inflicted hammer blows to the head were identified. For example, self-inflicted hammer blows may be identified by the absence of defensive wounds, injuries to the face and extracranial injuries and the finding that they are most commonly distributed in an area usually covered by a ‘zuchetto’ skull cap.

The Impression of Blood Droplets on Solid Surface and its Evaluation with Bloodstain Pattern Analysis, A Cross Section Forensic Study

Task: The aims and objectives of current study were to identify the values of bloodstain pattern analysis for blood droplets on solid surface in forensic sciences. Methodology: Study design: Present study was conducted in different medical institutions of Lahore from November 2021to March 2022. Crime scene (Blood droplets on solid surface): In current study for research purpose few blood droplets of 2 individuals were dropped on different solid surfaces and consider it as crime scene. Sample collection: In this study total 10 blood samples were collected from different individuals for cross match with the droplets of blood sample collected from solid surfaces. 2, individuals how dropped their blood droplets on solid surfaces were also included in total participants of present study. Blood droplets from solid surfaces were collected with the help of cotton swab techniques. DNA analysis: With the application of Polymerase chain reaction such analysis performed and DNA released from the cell by extraction and measured the amount of genetic material than amplified its copies and separated these amplified copies from each other. The qualitatively and quantitatively comparing of DNA evidence samples are referred as DNA profiles and checking the technical correctness of analyst reports was its quality assurance.

A rare case of ligature strangulation using a dental unit: Distinguishing suicide from homicide in a death scene investigation

Ligature strangulation is more common in homicides and is rarely seen in suicides and sexual asphyxia involving neck compression. We report a rare case of a dentist found dead of ligature strangulation next to a dental unit. The ligature was attached to the window frame, wrapped tightly around the neck once with a noose, and tied at the midpoint of the neck and at the head of the dental chair. A death scene and medicolegal investigation suggested suicidal ligature strangulation. The victim was squatting next to the dental unit with the control panel within reach. Pressing Button 1 (the recline button) would have tightened the ligature around the neck. A container containing pink nylon ribbon was found near the victim. The position of the knot at the front of the neck was consistent with suicide. Bloodstain pattern analysis confirmed the longitudinal flow pattern. No other remarkable findings were observed. Nobody had visited the clinic, autopsy found no drugs in his system, and the environment was undisturbed. Homicide was ruled out. According to witnesses, the victim had been in litigation with the owner of the building where his clinic was located. There were no reports of the victim having engaged in any unusual sexual or autoerotic activity. He had not received any death threats. Approximately 1 h before his death, he sent a suicide text message to his wife. Our case highlights the importance of distinguishing between suicide and homicide, especially in cases of ligature strangulation.

Insights Into Bloodstain Degradation and Time Since Deposition Estimation Using Electrochemistry

Blood is an important type of forensic evidence because it can be used for source identification, toxicological analyses, and bloodstain pattern interpretation. Determining the time that bloodshed occurred, often described as the bloodstain’s time since deposition (TSD), has important implications for crime scene investigation. In this work, we focus on using electrochemical methods to monitor the gradual oxidative changes and electron-transfer reactions of hemoglobin (Hb) occurring in degrading bloodstains using differential pulse and hydrodynamic voltammetry. Bloodstains were monitored across a two-week time series in five different temperature conditions. Linear mixed models generated from the differential pulse voltammograms (DPV) suggested that 7 of 27 variables related to the redox reactions associated with the blood film were significantly correlated with time (p< 0.033). Of these correlated variables, all were related to the reduction of bound oxygen to hemoglobin or the oxidation of hemoglobin degradation products within the film. Hydrodynamic voltammetry demonstrated that hemoglobin retains its catalytic activity for oxygen reduction when aged on an electrode surface with a shift to greater peroxide formation the longer it is aged. The time series models are improved when the biological replicate is considered as a random effect, and as well as when peak area ratios are included in the model. Interestingly, using linear mixed models we observed a significant change in redox response at the 96-h time point (p< 0.043) regardless of temperature condition. Overall, we demonstrate preliminary support for DPV as a technique for TSD estimation of bloodstains.

Automatic Classification of Bloodstains with Deep Learning Methods

The classification of detected bloodstains into predetermined categories is a crucial component of the so-called bloodstain pattern analysis. As in other forensic disciplines, deep learning methods may help to reduce human subjectivity within this process, may increase the classification accuracy, shorten the calculation time and thus, enable high-throughput analysis. In this work, an approach is presented in which a convolutional neural network (Inception v3) was trained from 965 drip stains (passive origin) and 1595 blood spatters (active origin). The trained CNN was evaluated with a test data set consisting of 366 images of drip stains and blood spatters. The success rate was 99.73% which suggests that neural networks could also be used to automatically classify other classes of bloodstain patterns to speed up the investigation process in the future.

Investigation of the Criminal Suspects in Local Population Through Forensic Indicators, A Cross-Sectional Study

The aims and objectives of current study were to identify the real criminal persons from suspects through modern scientific forensic technology. Methodology: A wooden stick, assaulted person’s cloth with blood strains, blood strains on the ground and some hairs from the hand of victim were collected at crime scene. And samples of accused ones were also collected. Dry blood sample was collected from the crime scene by Bloodstain Pattern Analysis while 3ml blood sample of 100 office employees were taken in the tube and was centrifuged at x10000 rpm for analysis and DNA profiling. Fingerprints were analyzed from the wooden stick by Latent printing and were compared to suspects. DNA sample also collect from hair follicle for analysis. Results: DNA profiling of Aggravated Assault on different biological aspects were analyzed, the analysis were showed that blood strains on assaulted person’s cloth has cross matching regression stranded mean deviation (1.0± 0.01) with office employees and blood strains collected from ground also have cross matched correlation with (3.0± 0.03) suspects respectively. The mitochondrial DNA of hair follicles which was in hands of Aggravated Assault at the time of crime scene has a significant (P<0.05) cross match with suspects (2.10± 0.02) DNA. Conclusion: The findings of this study through biological and non-biological aspects were significant (P<0.05). Total five persons were marked as criminal from all selected suspects by considering their DNA profile cross matching and finger prints cross match correlations with Aggravated Assault. Keywords: Aggravated Assault, suspects. Deoxyribonucleic acid

BLOODSTAIN PATTERN ANALYSIS AS SCIENTIFIC EVIDENCE IN THE JUDICIAL PROCESS. STATE OF THE MATTER IN SPAIN AND LEGE FERENDA PROPOSAL

El análisis de patrones de manchas de sangre brinda al proceso judicial la oportunidad de proporcionar, estudiar y evaluar pruebas veraces e imparciales, lo que facilita la toma de decisiones objetivas por parte del jurado. 
 Sin embargo, existe un desconocimiento de la disciplina y de las normas legislativas relacionadas con la formación de expertos y sus informes en España. Esto complica el desarrollo de este tema y reduce su veracidad.
 Con la intención de brindar medidas que faciliten su crecimiento de manera garante, se ha analizado la legislación, las sentencias relacionadas y los estándares de formación de los policías encargados de la investigación de patrones de manchas de sangre.
 El propósito es el de probar el valor del análisis de patrones de manchas de sangre como disciplina. La importancia de la función auxiliar que ejercen los peritos en esta materia se pondrá de manifiesto también a través de los informes presentados en distintos procesos judiciales.

A particulate blood analogue based on artificial viscoelastic blood plasma and RBC-like microparticles at a concentration matching the human haematocrit.

There has been enormous interest in the production of fluids with rheological properties similar to those of real blood over the last few years. Application fields range from biomicrofluidics (microscale) to forensic science (macroscale). The inclusion of flexible microparticles in blood analogue fluids has been demonstrated to be essential in order to reproduce the behaviour of blood flow in these fields. Here, we describe a protocol to produce a whole human blood analogue composed of a proposed plasma analogue and flexible spherical microparticles that mimic the key structural attributes of RBCs (size and mechanical properties), at a concentration matching the human haematocrit (∼42% by volume). Polydimethylsiloxane (PDMS) flexible microparticles were used to mimic RBCs, whose capability to deform is tunable by means of the mixing ratio of the PDMS precursor. Their flow through glass micronozzles allowed us to find the appropriate mixing ratio of PDMS to have approximately the same Young's modulus (E) as that exhibited by real RBCs. Shear and extensional rheology and microrheology techniques were used to match the properties exhibited by human plasma and whole blood at body temperature (37 °C). Finally, we study the flow of our proposed fluid through a microfluidic channel, showing the in vitro reproduction of the multiphase flow effects taking place in the human microcirculatory system, such as the cell-free layer (CFL) and the Fåhræus-Lindqvist effect. A macroscale application in the field of forensic science is also presented, concerning the impact of our blood analogue droplets on a solid surface for bloodstain pattern analysis.