Evidential significance of multiple fracture patterns on the glass in forensic ballistics

Abstract

Background: In the current scenario, glass plays a vital contribution in our standard everyday life. Fractured and fragmented glasses are most commonly encountered at the crime scene. During the commission of the crime, glass breaks and shatters into fragments or into minute particles that serve as trace evidence and may provide a significant lead for the probe. The fracture of glass could be the consequence of an intentional act or unintentional act. For the forensic purpose, study of glass fractures, i.e., fractography has paramount importance as it can provide noteworthy data and encourages an assortment of assessments to investigate the case especially in the shooting cases where a firearm is used. Multiple fractures on a glass pane also have enough potential to establish an investigative link. Presently, air guns are being used in many of the cases due to their simple accessibility. There are a number of cases that have been reported that involved the use of air guns. Result: This study was conducted to evaluate the pattern of multiple fractures on the glass by the air rifle. For this purpose, glass panes of various thicknesses were test fired perpendicularly at a fixed range with an air rifle having round nose pellet. Measurements and analysis were made on some fixed parameter. Data was analyzed graphically and statistically to check the consistency in the trends. Conclusion: Consistency in the trends was observed, which is analyzed by the test for the goodness of fit. The findings of this work have provided some significant different perspectives that may effectively contribute to the criminal investigation.

Forensic Investigation of Bullet Holes for Determining Distance from Glass Fracture Analysis

“…Another study was done with air rifle on window panes of different thickness than in previous one to study multiple fractures [6]. Difference in hole diameter was found; it was concluded that hole diameter of first shot was larger than that of second shot in the transparent glass of 4mm, and 5mm thickness.…”

“…Cone fractures are observed to be caused by the penetration of high-velocity projectile, such as a bullet. As Griffiths states in his fracture experiment that fractures always start from pre-existing flaws that are termed as Griffith's flaw [6].…”

Towards the investigation of shooting incidents: evaluation of fracture pattern on polymethylmethacrylate sheet made by .22″ and .177″caliber air rifle

“…After the firing, samples were photographed, Radial and concentric cracks were counted directly. Hole diameter, Diameter of mist zone and Thickness of mist zone were measured by digital Vernier Caliper as discussed by Harshey et al (2017) and Tiwari et al (2019). For the validation of the hypothesis, statistical calculations i.e.…”

“…From the medico-legal point of view, the air gun has attracted various researchers towards the study of wound ballistics phenomenon, and it was found that air gun may cause bone micro-fractures, ocular injuries and even death also occurred (Schein et al, 1994;Wightman et al, 2010;Kieser et al, 2013;Stankov et al, 2013;Hsiao and Meng, 2018a;Simon et al, 2019). Along with this, terminal ballistic literature of air guns also experimented which strengthened the available literature and forensic investigation perspective (Wightman et al, 2013;Tiwari et al, 2019;Hsiao and Meng, 2018b).…”

Interpol review of glass and paint evidence 2016-2019

“…Tiwari et al. [ 67 ] varied thicknesses of glass to study the consistency of multiple fracture patterns when shot with an air rifle loaded with round nose pellets. Goodness of fit was used to analyze the data and found consistency within the fractures.…”