Bloodstain Pattern Analysis

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F Ramsthaler - One of the best experts on this subject based on the ideXlab platform.

  • Effect of anticoagulation therapy on drying times in Bloodstain Pattern Analysis
    International Journal of Legal Medicine, 2017
    Co-Authors: F Ramsthaler, Ann-katrin Kröll, Marcel Verhoff, Christoph G. Birngruber, Matthias Kettner
    Abstract:

    In forensic case work, blood stain Pattern Analysis frequently aids in deducing the chain of actions or parts thereof taking place during an event leading to blood loss. Wiped single blood stains and/or groups of blood stains are seen at a majority of complex crime scenes. The appearance of wiped blood stains depends on droplet volume and stain age (as a function of blood viscosity and the degree of stain skeletonization) and characteristics of the stained surface (i.e., texture, temperature). Furthermore, based on the biochemical and biophysical properties of blood, not only the drying processes, but also complex coagulation cascades are relevant to the assessment of wiped blood stains. This study was designed to determine if anticoagulation therapies markedly affect the wipeability of blood stains over times elapsed since deposition and the overall drying process. A total of 813 blood stains, originating from donors being treated with acetylsalicylic acid (ASA), clopidogrel + ASA, low-molecular-weight heparin, or rivaroxaban, were dropped on common household tiles. Wipeability at an ambient temperature of 20 °C was tested for 22 time periods (1, 2, 3, 5, 10, 15…105 min since deposition). Whereas stains consisting of untreated blood were dried within 55 min, wipeability of all droplets originating from donors with prior anticoagulation treatment showed pronounced delays compared with the control, ranging from 20 min (ASA and clopidogrel + ASA) to 45 min (rivaroxaban). This pronounced effect was not seen in earlier studies, which might be explained by the higher volume of droplets used in this study, which resulted in a shift in relevance from drying to clotting processes. Significant differences between the drying times of the various anticoagulation regimes might be attributed to anticoagulant activity against different targets in the coagulation cascades. In conclusion, anticoagulation treatment prior to blood loss significantly affected the wipeability of blood stains. Anticoagulation therapy should therefore be taken into account in the Analysis of blood stain Patterns.

  • Impact height and wall distance in Bloodstain Pattern Analysis—what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, P Schmidt, A. Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

  • impact height and wall distance in Bloodstain Pattern Analysis what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, A. Schmidt, Peter H Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

  • Bubbles"--a spot diagnosis.
    Journal of Forensic Sciences, 2010
    Co-Authors: Matthias Kettner, F Ramsthaler, Axel Schnabel
    Abstract:

    :  Aspiration of blood is a phenomenon observed in violent and natural death scenarios. Bloodstain Patterns evolving from expectoration of aspired blood may look suspicious of a violent genesis and thus mislead crime scene investigators. In the present case, a woman was found lying in a pool of blood on the kitchen floor. Furthermore, Bloodstains covered her face, clothing, and surrounding furniture and walls. Bloodstain Pattern Analysis and medicolegal inspection of the suspected scene of crime were carried out and revealed dispersed stains with enclosed gas bubbles in the absence of signs of physical violence leading to the assessment of a natural manner of death. The Bloodstains were attributed to expiration of blood because of an internal bleeding. Medicolegal autopsy confirmed the on-site diagnosis as a fatal esophageal varix rupture was found.

Daniel Attinger - One of the best experts on this subject based on the ideXlab platform.

  • implications of two backward blood spatter models based on fluid dynamics for Bloodstain Pattern Analysis
    Forensic Science International, 2019
    Co-Authors: P M Comiskey, Alexander L Yarin, Daniel Attinger
    Abstract:

    Abstract Bloodstain Pattern Analysis (BPA) is an integral part of crime scene investigation. For violent crimes involving gunshots, standard practice in police departments worldwide have some physical limitations. For instance, the effect of gravity and air drag on trajectories of blood droplets are neglected using current reconstruction methods, which results in a well-known overestimation of the height of the source of blood. As a consequence, more sophisticated models for blood spatter trajectory reconstruction are being developed, two of which are highlighted in the present work. They allow the prediction of Bloodstain Patterns produced from backward spattered blood droplets from blunt and sharp bullets. Our recent models attribute the splashing of blood to the Rayleigh–Taylor instability which arises when blood is accelerated towards lighter air. This physically-based description comes with the powerful predictive capability to correlate features of Bloodstain Patterns with the specific bullet and gun that produced them, as well as with the body position. The results of the numerical models were compared with four experiments simulating blood spatter deposition on a vertical wall through the number of stains produced, average stain area, and average impact angle at the surface, and the agreement found is fairly good. Moreover, further insight is obtained by probing and explaining the influence of observable parameters on the resulting spatter Pattern, with the goal of aiding BPA experts evaluating a crime scene.

  • a data set of Bloodstain Patterns for teaching and research in Bloodstain Pattern Analysis gunshot backspatters
    Data in Brief, 2019
    Co-Authors: Daniel Attinger, Ricky Faflak, Bryce A Struttman, Kris De Brabanter, P M Comiskey, Alexander L Yarin
    Abstract:

    Abstract This is a data set of blood spatter Patterns scanned at high resolution, generated in controlled experiments. The spatter Patterns were generated with a rifle or a handgun with varying ammunition. The resulting atomized blood droplets travelled opposite to the bullet direction, generating a gunshot backspatter on a poster board target sheet. Fresh blood with anticoagulants was used; its hematocrit and temperature were measured. The main parameters of the study were the bullet shape, size and speed, and the distance between the blood source and target sheet. Several other parameters were explored in a less systematic way. This new and original data set is suitable for training or research purposes in the forensic discipline of Bloodstain Pattern Analysis.

  • a data set of Bloodstain Patterns for teaching and research in Bloodstain Pattern Analysis impact beating spatters
    Data in Brief, 2018
    Co-Authors: Daniel Attinger, Tyler Bybee, Kris De Brabanter
    Abstract:

    Abstract This is a data set of 61 blood spatter Patterns scanned at high resolution, generated by controlled impact events corresponding to forensic beating situations. The spatter Patterns were realized with two test rigs, to vary the geometry and speed of the impact of a solid object on a blood source – a pool of blood. The resulting atomized blood droplets travelled a set distance towards a poster board sheet, creating a blood spatter. Fresh swine blood was used; its hematocrit and temperature were measured. Main parameters of the study were the impact velocity and the distance between blood source and target sheet, and several other parameters were explored in a less systematic way. This new and original data set is suitable for training or research purposes in the forensic discipline of Bloodstain Pattern Analysis.

  • Bloodstains on woven fabric: Simulations and experiments for quantifying the uncertainty on the impact and directional angles.
    Forensic Science International, 2017
    Co-Authors: Prashant Agrawal, Laurel Barnet, Daniel Attinger
    Abstract:

    Abstract Bloodstain Pattern Analysis considers stains on various porous and non-porous surfaces, for the purpose of crime scene reconstruction. On non-porous surfaces, several studies relate the impact conditions of drops to the inspection of stain shapes. Stains on porous surfaces like fabrics have been relatively less explored. The phenomenon of imbibition of blood into the fabric after impact adds further complexity in retrieving information on the impacting conditions. The present work studies experimentally and numerically the formation of drip stains on a woven fabric. The proposed methodology first relies on Darcy’s law to measure the imbibition characteristics of the fabric through a set of simple imbibition experiments. Next, the fabric properties are fed into a numerical model to predict the growth of the Bloodstain after impact of a droplet. Experiments at different drop release heights and impact angles are compared with the numerical simulations. The uncertainties induced by the fabric on the determination of the impact and directional angles are explained and quantified.

  • how important is it to consider target properties and hematocrit in Bloodstain Pattern Analysis
    Forensic Science International, 2016
    Co-Authors: Prashant Agrawal, Daniel Attinger
    Abstract:

    Trajectory reconstruction from inspection of Bloodstain Patterns is relevant to crime scene investigation. While the influence of target properties on trajectory reconstruction has been often qualitatively discussed, it has rarely been quantified. Similarly, a few impact studies measure the viscosity of the blood used in impact experiments. In this work, the impact of blood drops is investigated on targets with a range of surface roughness and surface material. The maximum spreading is characterized using a spreading correlation, which relates the ratio of stain diameter to drop diameter with the non-dimensional numbers Reynolds number and Ohnesorge number. The process for obtaining individual spreading correlations for each of the target substrates and for measuring the viscosity of the respective blood samples is described extensively. The error in estimating the drop release height, associated with using an impact correlation unspecific to the target of interest, is estimated analytically and numerically using experimental data. A similar Analysis is done when the hematocrit of the blood is assumed rather than measured. Both assumptions lead to significant errors in estimating the release height of a blood droplet.

Matthias Kettner - One of the best experts on this subject based on the ideXlab platform.

  • Effect of anticoagulation therapy on drying times in Bloodstain Pattern Analysis
    International Journal of Legal Medicine, 2017
    Co-Authors: F Ramsthaler, Ann-katrin Kröll, Marcel Verhoff, Christoph G. Birngruber, Matthias Kettner
    Abstract:

    In forensic case work, blood stain Pattern Analysis frequently aids in deducing the chain of actions or parts thereof taking place during an event leading to blood loss. Wiped single blood stains and/or groups of blood stains are seen at a majority of complex crime scenes. The appearance of wiped blood stains depends on droplet volume and stain age (as a function of blood viscosity and the degree of stain skeletonization) and characteristics of the stained surface (i.e., texture, temperature). Furthermore, based on the biochemical and biophysical properties of blood, not only the drying processes, but also complex coagulation cascades are relevant to the assessment of wiped blood stains. This study was designed to determine if anticoagulation therapies markedly affect the wipeability of blood stains over times elapsed since deposition and the overall drying process. A total of 813 blood stains, originating from donors being treated with acetylsalicylic acid (ASA), clopidogrel + ASA, low-molecular-weight heparin, or rivaroxaban, were dropped on common household tiles. Wipeability at an ambient temperature of 20 °C was tested for 22 time periods (1, 2, 3, 5, 10, 15…105 min since deposition). Whereas stains consisting of untreated blood were dried within 55 min, wipeability of all droplets originating from donors with prior anticoagulation treatment showed pronounced delays compared with the control, ranging from 20 min (ASA and clopidogrel + ASA) to 45 min (rivaroxaban). This pronounced effect was not seen in earlier studies, which might be explained by the higher volume of droplets used in this study, which resulted in a shift in relevance from drying to clotting processes. Significant differences between the drying times of the various anticoagulation regimes might be attributed to anticoagulant activity against different targets in the coagulation cascades. In conclusion, anticoagulation treatment prior to blood loss significantly affected the wipeability of blood stains. Anticoagulation therapy should therefore be taken into account in the Analysis of blood stain Patterns.

  • Impact height and wall distance in Bloodstain Pattern Analysis—what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, P Schmidt, A. Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

  • impact height and wall distance in Bloodstain Pattern Analysis what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, A. Schmidt, Peter H Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

  • Bubbles"--a spot diagnosis.
    Journal of Forensic Sciences, 2010
    Co-Authors: Matthias Kettner, F Ramsthaler, Axel Schnabel
    Abstract:

    :  Aspiration of blood is a phenomenon observed in violent and natural death scenarios. Bloodstain Patterns evolving from expectoration of aspired blood may look suspicious of a violent genesis and thus mislead crime scene investigators. In the present case, a woman was found lying in a pool of blood on the kitchen floor. Furthermore, Bloodstains covered her face, clothing, and surrounding furniture and walls. Bloodstain Pattern Analysis and medicolegal inspection of the suspected scene of crime were carried out and revealed dispersed stains with enclosed gas bubbles in the absence of signs of physical violence leading to the assessment of a natural manner of death. The Bloodstains were attributed to expiration of blood because of an internal bleeding. Medicolegal autopsy confirmed the on-site diagnosis as a fatal esophageal varix rupture was found.

M. Windgassen - One of the best experts on this subject based on the ideXlab platform.

  • Impact height and wall distance in Bloodstain Pattern Analysis—what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, P Schmidt, A. Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

  • impact height and wall distance in Bloodstain Pattern Analysis what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, A. Schmidt, Peter H Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

A. Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • Impact height and wall distance in Bloodstain Pattern Analysis—what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, P Schmidt, A. Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.

  • impact height and wall distance in Bloodstain Pattern Analysis what Patterns of round Bloodstains can tell us
    International Journal of Legal Medicine, 2015
    Co-Authors: Matthias Kettner, M. Windgassen, C Von Wagner, A. Schmidt, Peter H Schmidt, F Ramsthaler
    Abstract:

    Bloodstain Pattern Analysis is a routine procedure in forensic cases that involve bleeding wounds. It utilizes geometric principles to determine the sequence of actions causing the bloodshed and the area of origin, that is, from where the blood originated. The Patterns formed by circular Bloodstains from drops of blood that hit adjacent surfaces at a 90-degree angle are thought to provide indications of the height of the impact. In this study, blunt force exerted against a pool of blood, which was used as a surrogate for a bleeding wound, was carried out for five different impact-to-wall distances. The blunt force consisted of a hammer head that was dropped from a height of 1.5 m. High-speed photography of the impact and trajectories of the projected blood droplets was analysed. The Patterns containing Bloodstains produced by the droplets were analysed by measuring the circular Bloodstains within the Patterns. All the experiments showed that there were two distinct Patterns or clusters of circular Bloodstains that occurred at different heights above the impact site. The two Patterns were a result of different fractions of blood that were projected in a garland or crown-like form of a “Worthington splash” after impact. The findings suggest that Patterns of circular Bloodstains cannot be used as direct indicators of impact height, but combined Analysis of their clusters may lead to indirect determination of impact-to-wall distance and area of origin.