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Bloodstain Pattern Analysis

The Experts below are selected from a list of 525 Experts worldwide ranked by ideXlab platform

F Ramsthaler – 1st expert 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, A. Schmidt, M. Windgassen, P Schmidt, C Von Wagner, 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, A. Schmidt, M. Windgassen, C Von Wagner, 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.

Daniel Attinger – 2nd expert 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.

Matthias Kettner – 3rd expert 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, A. Schmidt, M. Windgassen, P Schmidt, C Von Wagner, 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, A. Schmidt, M. Windgassen, C Von Wagner, 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.