Blood drop size in passive dripping from weapons

Kabaliuk, Natalia; Jermy, Mark; Morison, Ken R.; Stotesbury, Theresa; Taylor, Michael; Williams, E.G.

doi:10.1016/j.forsciint.2013.02.023

Cited by 21 publications

(17 citation statements)

References 38 publications

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“…The present findings give another good example of the importance of high‐speed digital video analysis when interpreting bloodstains. We could confirm earlier research by Donaldson et al and Kabaliuk et al , who state that with high‐speed imaging, physical characteristics of blood and their fluid dynamics can be visualized more accurately and thus can be better understood.…”

Section: Discussionsupporting

confidence: 90%

Analyzing the Dynamics and Morphology of Cast‐off Pattern at Different Speed Levels Using High‐speed Digital Video Imaging

Kunz

Adamec

Grove

2016

Journal of Forensic Sciences

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During a bloodstain pattern analysis, one of the essential tasks is to distinguish between different kinds of applied forces as well as to estimate their level of intensity. In this study, high-speed digital imaging has been used to analyze the formation of cast-off patterns generated by a simulated backswing with a blood-bearing object. For this purpose, 0.5 mL blood was applied evenly over the last 5 cm of a blade simulant. Bloodstains were created through the controlled acceleration of a backswing at different speed levels between 1.1 m/sec and 3.8 m/sec. The flight dynamics of blood droplets were captured with an Olympus i-Speed 3 high-speed digital camera with a Nikon AF Nikkor 50 mm f/1.8 D lens and analyzed using the Olympus i-Speed 3 Viewer software. The video analysis showed that, during the backswing, blood droplets would move toward the lower end of the knifepoint and would be tangentially thrown off. These droplets impacted on the horizontal surface according to the arc of the swing. An increase in velocity led to longer cast-off patterns with distinct morphological characteristics. Under laboratory conditions, bloodstain pattern analysis allows certain conclusions about the intensity of a backswing and provides instructions on the position of the offender. However, due to the number of unknown variables at a crime scene, such interpretation of cast-off patterns is extremely limited and should be performed with extreme caution.

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Section: Discussionsupporting

confidence: 90%

Analyzing the Dynamics and Morphology of Cast‐off Pattern at Different Speed Levels Using High‐speed Digital Video Imaging

Kunz

Adamec

Grove

2016

Journal of Forensic Sciences

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“…However, this method might also be used for analyzing other kinds of bloodstain patterns. For example, the drip trail pattern (stains resulting from droplets, created solely by gravity) could be investigated to determine the average height of deposition 28 . Moreover, cast-off patterns (patterns created due to the rapid movement of a bloody object) could be investigated to determine the swing radius and maybe even the radial velocity of the object 29 .…”

Section: Discussionmentioning

confidence: 99%

Bloodstain Pattern Analysis: implementation of a fluid dynamic model for position determination of victims

Laan

Bruin

Slenter

et al. 2015

Sci Rep

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Bloodstain Pattern Analysis is a forensic discipline in which, among others, the position of victims can be determined at crime scenes on which blood has been shed. To determine where the blood source was investigators use a straight-line approximation for the trajectory, ignoring effects of gravity and drag and thus overestimating the height of the source. We determined how accurately the location of the origin can be estimated when including gravity and drag into the trajectory reconstruction. We created eight bloodstain patterns at one meter distance from the wall. The origin’s location was determined for each pattern with: the straight-line approximation, our method including gravity, and our method including both gravity and drag. The latter two methods require the volume and impact velocity of each bloodstain, which we are able to determine with a 3D scanner and advanced fluid dynamics, respectively. We conclude that by including gravity and drag in the trajectory calculation, the origin’s location can be determined roughly four times more accurately than with the straight-line approximation. Our study enables investigators to determine if the victim was sitting or standing, or it might be possible to connect wounds on the body to specific patterns, which is important for crime scene reconstruction.

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“…The size of the primary drop was reported to decrease from a blunt to a sharp object [8]. On similar lines, if the possible sources of a blood drop stain or trail could be identified then that would contribute to the reconstruction process.…”

Section: Proposed Methodsmentioning

confidence: 87%

“…Knock et al [7] proposed a mathematical model to predict the impact velocity and position of the source of a bloodstain. In coherence with the perspective of Ross [6], Kabaliuk et al [8] studied the size of droplets free falling from objects that were representative of hand held objects. Kabaliuk et al [8] reported that the number of accompanying droplets increased linearly in accordance with the increase in the object size.…”

Section: Literature Reviewmentioning

confidence: 99%

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2018

FSAR

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Blood drop size in passive dripping from weapons

Cited by 21 publications

References 38 publications

Analyzing the Dynamics and Morphology of Cast‐off Pattern at Different Speed Levels Using High‐speed Digital Video Imaging

Analyzing the Dynamics and Morphology of Cast‐off Pattern at Different Speed Levels Using High‐speed Digital Video Imaging

Bloodstain Pattern Analysis: implementation of a fluid dynamic model for position determination of victims

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