Unusual blood spatter patterns on the firearm and hand: A backspatter analysis to reconstruct the position and orientation of a firearm

doi:10.1016/j.forsciint.2013.02.012

Forensic Science International

Volume 228, Issues 1–3, 10 May 2013, Pages e54-e57

https://doi.org/10.1016/j.forsciint.2013.02.012 Get rights and content

Abstract

When it comes to firearm fatalities, the main goal of forensic analysis is to distinguish firearm suicides from homicides and accidents. Apart from the location of the entrance wound, wound path trajectory and gunshot residue, blood stain pattern analysis of gunshot-related backspatter on the hands of the victim can be an essential tool not only to determine which hand was holding the firearm, but also to reconstruct the position from which a weapon was fired. We present a case of a 90-year-old man, who was found dead in his house. Because of unclear circumstances and an unusual position of the deceased with a gunshot entrance wound to the right temporal region and a firearm found on the left side of his body, an autopsy was performed. Due to the unusual bloodspatter stains on the hands and the firearm, it was possible to deduce the position and orientation of the hands and the firearm of the deceased. We could reconstruct that the man held the weapon in his right hand, using the left hand to stabilise the firearm and the right thumb to pull the trigger. A contact shot to the right temple led to central regulatory failure due to extensive brain injury. The manner of death was concluded to be a suicide.

Section snippets

Case background

A 90-year-old man was discovered dead in his house. He was found sitting in an upright position, leaning back against a folded deck chair (Fig. 1). The right side of his body was profusely covered in blood. A blood pool could also be seen on the ground next to him, oriented towards his right elbow. In the right temporal region, there was a circular wound, which was covered with blood. On the left side of the body, a pistol was detected (Fig. 2). The left arm rested on his left thigh. According

Weapon

The weapon used was a ‘Walter PPK 7.65’, a blowback-operated semi-automatic pistol with a traditional double-action trigger mechanism and a single-column magazine, calibre 7.65 mm (Fig. 3). The pistol was in the lawful possession of the deceased.

Uncharacteristic bloodstains were found on the firearm. The distribution of blood showed no preferential site. Inconsistent droplets were widely spread over the weapon. An angle of incidence could not be calculated. Projected patterns were mainly found

Autopsy report

The autopsy findings suggested a contact gunshot wound to the right temple. The bullet trajectory was from right to left in the horizontal plane. The wound channel within the brain led from the right frontal area below the temporal lobe slightly oblique into the cerebrum and through the middle part of the left temporal lobe, crossing the midline just before the optic chiasm.

The examination of the entrance wound on the right temporal region with a stereomicroscope revealed a muzzle imprint, an

Backspatter

The droplets were predominantly distributed on the extensor side of the fingers and the radial aspect of the hands. Several elongated droplets in the shape of ‘exclamation marks’ found on the middle joint of the right index finger pointed approximately towards the fingertip. Similar, parallel patterns were detected on the base joint, mostly with the same direction. Individual droplets at the inner part of the index finger were aligned towards the palm of the hand (Fig. 5, Fig. 6). Additionally,

Discussion

In order to be able to reconstruct the events at a crime scene, forensic investigators study the shapes, sizes and distribution of bloodstains. Together with autopsy findings about injuries, a medically and scientifically based reconstruction of possible wounding mechanisms is possible [5].

Based primarily on the characteristics and location of the entrance wound and direction of bullet path, the presented case would be classified as a suicide. [6] However, the final position of the weapon on

Limitation

Even though the bloodstains on the hands showed no trapped bubbles or roundish recesses, it cannot be excluded that individual droplets might be the result of expirated blood. However, the autopsy results and our calculations have shown that this possibility would not alter the weapon's position.

Conclusion

This case was remarkable for an unusual distribution of backspatter, which could be explained by an abnormal position of the trigger and supporting hand during fire.

Especially in doubtful cases, a careful bloodstain pattern analysis of backspatter findings on the hands can help to reconstruct the position of the weapon and distinguish between a homicide, suicide and accident.

Conflicts of interest

This article is a result of forensic reconstruction work, which was done for the police. The research was not funded and there is no actual or potential conflict of interest in relation to this article.

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Case reportUnusual blood spatter patterns on the firearm and hand: A backspatter analysis to reconstruct the position and orientation of a firearm

Abstract

Section snippets

Case background

Weapon

Autopsy report

Backspatter

Discussion

Limitation

Conclusion

Conflicts of interest

Forensic Sci. Int.

Forensic Sci. Int.

Blood-spatter patterns: hands hold clues for the forensic reconstruction of the sequence of events

Am. J. Forensic Med. Pathol.

Backspatter on the firearm and hand in experimental close-range gunshot to the head

Am. J. Forensic Med. Pathol.

Backspatter from experimental close-range shots to the head. II. Microbackspatter and the morphology of bloodstains

Int. J. Legal Med.

Case report
Unusual blood spatter patterns on the firearm and hand: A backspatter analysis to reconstruct the position and orientation of a firearm