Post-blast histological changes to three animal bones exposed to close-range chemical detonation.

A range of investigative practices to aid explosive-related death investigations currently exist, although the use of histopathological bone samples to diagnose blast exposure and the distance of individuals from the blast source has not been previously reported. Forensic histopathology has been used effectively on soft tissue samples to define blast-related injuries effectively, analysing human organs such as the lungs, brain, liver, and skeletal muscles, providing important and useful forensic pathology interpretations. However, no studies currently exist examining the post-blast histological changes in human or animal bones subjected to blasts for forensic pathology practice, despite the opportunity that hard tissue bone samples present, given their significantly lower rate of decomposition over soft tissue. This study presents the first evidence-based findings on the post-blast histological changes in three animal bones when exposed to close-range chemical detonation (C4). The study's qualitative findings highlight critical changes in the tissue architecture of three different animal bone sources due to blast effects with range from the blast source. This emphasises the potential use of histopathological bone sample analysis in future blast-related death investigations, while providing ideas to further explore this work using larger-scale experiments and post-blast case studies in aid of applying this work to human samples and forensic pathology practice.

Ricochet of 9 mm pistol bullets on glazed ceramic tiles: An empirical study in support of shooting incident reconstruction.

Experimental ricochet data on the most commonly found bullet-target combinations in shooting incidents are contemporary necessity in conducting ricochet analysis during shooting reconstructions. As bullet ricochet behavior and associated evidence production are affected by various factors, understanding specific phenomena related to each bullet-target combination is essential for shooting investigators to reconstruct bullet ricochet incidents accurately. However, there is a significant lack of empirical data in this area despite the significant demand. Building on a previous study conducted with rifle bullets, this empirical study explores the ricochet behavior and surface evidence when 9 mm Luger pistol bullets ricochet off glazed ceramic wall and floor tiles. The study highlights the critical angles of bullets for floor and wall tiles (14.8 degrees and 16.6 degrees, respectively), and different bullet ricochet trends when 9 mm bullets ricochet off standard wall and floor tiles. This paper introduces for the first time in a ricochet event, the "caterpillar effect" or "caterpillar impact mark" and the first observation of the "nucleus" ricochet mark for pistol caliber bullet ricochets, both of which are important novel findings. This study further demonstrates the significance of undergoing practical and relevant ricochet experimentation for the accurate reconstruction of shooting incidents.

An empirical study on the close-range post-ricochet orientation of AK bullets (7.62 mm × 39 mm).

Most of the injuries and deaths from ricocheting bullets in shooting incidents are usually reported due to misaimed shots that had ricocheted close to the victims. Although the destabilisation of ricocheted bullets during their ricochet flights is a generally known phenomenon, no significant quantitative-based scientific studies have attempted to understand bullets' post-ricochet orientations at close distances. This empirical study explores close-range post-ricochet orientations of AK bullets (7.62 mm × 39 mm) on a range of domestic surface types typically encountered during bullet ricochet incidents. This study has revealed that ricocheting AK bullets off of various wood types and tile samples produce side-on impacts into closely located targets following a rightwards yaw action. It has also been shown that AK bullets ricocheting off concrete and cement samples at 5-degree incident angles produced nose-forward impacts on paper witness screens, similar to an orthogonal impact of a direct-fired shot. The findings present important new information on the post-ricochet yawing behaviour of AK bullets, which has the potential to aid future shooting reconstructions in which victims are hit by closely ricocheted bullets.

AK bullet (7.62 × 39 mm) holes on 1-mm sheet metal: A forensic-related study in aid of bullet trajectory reconstruction.

Bullet holes play a major role in the trajectory determination of fired bullets, potentially suggesting where the shots were fired from. Few methods are currently employed to estimate the angles of incidence of fired bullets using bullet holes. The literature has stressed that knowledge about the impact behavior of the specific bullet-substrate interfaces, including the most viable method for estimating the angle of incidence of that combination, requires empirical testing to enable successful analysis. The perforating bullet hole characteristics of AK bullets fired into 1-mm sheet metal over a range of angles of incidence have been documented in this study to aid bullet trajectory determination. A strong inverse relationship has been demonstrated between particular impact mark dimensions and the angles of incidence, revealing the possibility of using these dimensions to predict the angles of incidence for AK bullets perforating 1-mm sheet metal in actual crime scenes. This study has further confirmed the existence of a recently reported phenomenon for impacts related to this projectile-substrate combination, the "double-headed impact mark," and relationships with the angles of incidence of fired AK bullets. While suggesting an alternative and confirmative new method to understand the angles of incidence of fired AK bullets in 1-mm sheet metal using measured bullet defects, the study highlights a complex deviation phenomenon and a potential error that could occur when determining bullet trajectories using probing, stringing, or laser methods for the impact conditions described.