Cranial Backspatter Pattern Production Utilizing Human Cadavers

Rossi, Celestina; Herold, Lynne D.; Bevel, Tom; McCauley, Leslie; Guadarrama, Stephanie

doi:10.1111/1556-4029.13713

Cited by 13 publications

(5 citation statements)

References 15 publications

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“…, there is still no consensus on which experimental setup is best to simulate the complexity of gunshot spatter patterns in realistic conditions, where blood is located within a complex structure involving body tissues and blood vessels, covered by skin, clothes, or hair. Head of calves , a human cadaver filled with blood , foams or sponges soaked in blood , or cavities filled with blood have been used. Experiments reported in this study used both soaked foams and cavities filled with blood as the blood source, and the information on which blood source was used is specified.…”

Section: Methodsmentioning

confidence: 99%

Automatic Classification of Bloodstain Patterns Caused by Gunshot and Blunt Impact at Various Distances

Liu

Attinger

Brabanter

2020

Journal of Forensic Sciences

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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.

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Section: Methodsmentioning

confidence: 99%

Automatic Classification of Bloodstain Patterns Caused by Gunshot and Blunt Impact at Various Distances

Liu

Attinger

Brabanter

2020

Journal of Forensic Sciences

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“…22,[27][28][29]. Experimental research used either biological targets (living rabbits [25], living calves [19], living pig and pig heads [15], human cadavers [30], ovine and bovine heads [21]) or blood soaked sponges [5,[31][32][33]. All these approaches have particular advantages, but the common disadvantage was that the targets are not transparent and are dissimilar to human heads.…”

Section: Discussionmentioning

confidence: 99%

Study of backspatter using high-speed video of experimental gunshots

Schyma

Baumann

Madea

et al. 2020

Forensic Sci Med Pathol

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Backspatter is biological material that is ejected from the entry wound against the line of fire. This phenomenon was also observed in wound ballistic simulations using so called "reference cubes" (12 cm edge length, 10% gelatin, 4 °C, paint pad beneath the cover). High-speed video records from 102 experimental shots to these target models using full metal jacketed bullets in the calibers .32 auto, .38 special, 9 mm Luger and .357 Magnum were analyzed for chronology, morphological appearance and velocity of fluid ejection. Generally, a short tail splashing of surface material occurred when the bullet was penetrating the target. In 51 shots from distance (≥ 5 cm), regardless of caliber and shot range, a linear jet of fluid started in connection with the first collapse of the temporary cavity. The initial velocity of the jet was measured between 6 and 45 m/s. The jet was streaming on for about 60 to 100 ms with a stochastic deviation of ± 13° to the horizontal. Close range and contact shots showed earlier and faster (up to 330 m/s) backspatter depending on the cartridge and the gap between muzzle and target. Gaseous aerosol-like spray and cone-like spatter indicated an increasing influence of muzzle gases with decreasing shot range. Even under standardized experimental conditions, variations of backspatter were observed in near/contact shots.

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“…The location of stains furthest away (horizontally) from a blood source has been measured in studies of gunshots, where various guns, ammunition, settings and blood source have been used. Examples of blood sources include calves heads [18], a human cadaver filled with blood [19], foams or sponges soaked in blood [20,21], or cavities filled with blood [6]. Some experimental results of blood spatters were selected for comparison with theoretical and numerical studies, and the maximum experimental distances were 70cm [22] for backspatters and 4 meter for forward spatter [6].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Charts based on millions of fluid dynamics simulations provide a simple tool to estimate how far from its source a specific blood stain can be found

Attinger

2019

Forensic Science International

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The bloodstain pattern analyst sometimes has to judge if a given stain could originate from a specific location. A wide range of values of the maximum distance that a blood drop can travel have been reported from experiments, ranging from less than one meter to more than 10 meter. Here we formulate the problem in a fluid dynamics and data mining framework. The fluid dynamics is solved with Newton's classical equation of motion coupled with well-established models for the gravity and drag forces that bend the trajectories of drops. The parameters screened are the drop size, initial velocity and launch angle, as well as the height of a blood source and the ceiling height. Combining a wide range of values of those five parameter commended the performance of more than 5 million fluid dynamic simulations. Results of those simulations have been searched and mined for parameters directly measurable on a crime scene, such as the stain size and stain ellipticity. The results are presented in simple charts. Those charts are easy to use, and do not require any knowledge of fluid dynamics from the analyst. Disciplines Aerodynamics and Fluid Mechanics | Forensic Science and Technology | Mechanical Engineering Comments This is a manuscript of an article published as Attinger, Daniel. "Charts based on millions of fluid dynamics simulations provide a simple tool to estimate how far from its source a specific blood stain can be found."

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Cranial Backspatter Pattern Production Utilizing Human Cadavers

Cited by 13 publications

References 15 publications

Automatic Classification of Bloodstain Patterns Caused by Gunshot and Blunt Impact at Various Distances

Automatic Classification of Bloodstain Patterns Caused by Gunshot and Blunt Impact at Various Distances

Study of backspatter using high-speed video of experimental gunshots

Charts based on millions of fluid dynamics simulations provide a simple tool to estimate how far from its source a specific blood stain can be found

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