Homicide by unusual‐edged weapons: Forensic considerations of two cases

Homicide by stab wound is common worldwide. However, the use of unusual edged weapons is rarely reported in the forensic literature. Here, we report two cases of homicide involving a Japanese sword, or katana, and a sickle. Both of these weapons can create either stab or incised wounds with some particularities. In our cases, characteristics of the external wounds, internal injuries, and the depth of penetration raised the possibility of an unusual weapon. Meticulous forensic examination of these injuries (morphological characteristics, depth of penetration, trajectories, and cut marks in the bone) may allow the forensic expert to determine the type of weapon used.     

Observations and statistics relating to suicide weapons

The weapon at the scene of a suicide provides a resource in addressing such questions as frequency of blood in or on the weapon, location of the weapon with respect to the body, and evidence of firearm discharge residues on the hand. The first 195 weapons were tested for blood by a technique different from the following 202 weapons. Results were obtained which caused procedural changes in blood detection. Data are presented for frequency of blood in and on the muzzle of weapons, relative frequency of location of suicidal gunshot wound, and percent "positive" findings of gunshot residue metals on the hands. It was found that suicidal gunshot wounds were 3 times more frequent to the head than the chest, and that no significant difference was noted between males and females in this study. Scene photographs reveal that the suicide weapon is in or resting on the hand of the decedent 20% of the time with handguns and 11% of the time with long guns.     

肋软骨刺创的实验研究

本文对不同厚度的单刃刺器在肋软骨上形成的刺创口进行了肉眼和实体显微镜下的形态学观察，发现肋软骨上的刺创口与皮肤和骨质上的刺创口有着明显的不同。观察结果表明，创口的宽度不能反映刺器的厚度。一定厚度的单刃刺器所致的肋软骨上的创口肉眼及镜下无明显的钝角特征。据此，对在肋软骨上刺器所致刺创的凶器种类的推断提出新的见解。     

Macroscopic Analysis of Axe and Hatchet Trauma in Fleshed and Defleshed Mammalian Long Bones*

Abstract: Recently, the authors have noted that many studies involving the characterization of chopping weapon wounds have used either semi‐fleshed or defleshed bones (e.g., J Forensic Sci 2001; 46: 228). As these types of specimens do not reflect the full range of actual cases of postmortem dismemberment or perimortem trauma, 11 fresh pig (Sus scrofa) articulated hind limbs, with contiguous surrounding flesh, were inflicted with wounds using two axes and two hatchets. Defleshed humeri and femora were subjected to the same treatment. While there were no great differences found between the fleshed and defleshed specimens, characteristics observed including entrance site width and the presence of chattering were inconsistent with some aspects of Humphrey and Hutchinson’s study (J Forensic Sci 2001; 46: 228). Further, it was found that curve transverse and spiral fractures were prevalent in femora, while longitudinal fractures were prevalent in fibulae. Hence, fracture types may play a role in characterizing some wounds caused by chopping weapons.     

Microscopic characteristics of hacking trauma

The purpose of this study was to determine if it is possible to associate machetes, axes, and cleavers with the microscopic parallel striations they leave on the cut surfaces of the bone. Hacking trauma was experimentally inflicted on pig bones using machetes, axes, and cleavers. Negative impressions of both the cut surfaces of the bone and the weapon blades were analyzed using scanning electron microscopy. The results of this investigation indicate that it is possible to correlate a class of hacking weapons to trauma inflicted on bone by these weapons.     

WEAPON EFFECTS AND INDIVIDUAL INTENT TO DO HARM: INFLUENCES ON THE ESCALATION OF VIOLENCE*

In order to assess the roles of weapons and offender intentions in the outcomes of potentially violent events, we analyze more than 2,000 incidents described by offenders. We advance the study of weapons effects through a within‐person analysis that lets us control for all time‐stable characteristics of the offenders. Thus, we address the concern that relationships between type of weapon and incident outcome may be spurious because individuals with a greater propensity to do harm are more likely to use guns. Findings indicate that weapons have independent effects that differ across the stages of an event.     

Rifle wounds: a review of range and location as pertaining to manner of death

Given the prevalence of rimfire and centerfire rifle usage in both suicidal and homicidal cases, there is a paucity of articles in the literature that focus specifically on rifle wounds. Gunshot wounds, in general, have been extensively studied with articles focusing on the types of injuries, weapons used, wound locations and weapon range. We designed a study to examine the characteristics of rifle wounds, including both centerfire and rimfire rifles, especially pertaining to location and range of the wound. All deaths due to rifles examined at the Bexar County Medical Examiner's Office between 1988 and 2004 were reviewed. A total of 509 cases were identified, with 233 suicides and 266 homicides. We found that the average age of suicide victims (41.6 years) tended to be older than that of homicide victims (32.6 years). Suicides tended to be contact wounds to the head whereas homicides most often had multiple wound locations sustained from a distant range. The most common location to the head of suicidal wounds was intraoral whereas homicidal head wounds were more often to the temporoparietal region. We developed odds ratios for assessing the manner of death given a wound location or range; however, we caution that every case should be analyzed based upon it's unique circumstances and not solely its statistical probability.     

Relation of Kinetic Energy to Contact Wounds of the Head by Centerfire Rifles and Shotgun Slugs

Wounds of high‐energy centerfire rifles and shotguns represent distinctive injuries of forensic importance. Previous studies of contact wounds have shown variability in the potential of these weapons to produce bursting wounds of the head. The present study analyzed contact head wounds owing to 26 centerfire rifles and nine shotgun slugs and compared them with respect to weapon, ammunition, entry wound site, and projectile kinetic energy. The bursting effect, defined for this study as disruption of at least 50% of the head, occurred in 25/35 of cases and was related to kinetic energy. Bursting was associated with energies <2700 ft‐lbs in 12/22 cases and energies >2700 ft‐lbs in 13/13 cases. The volume of gunpowder gas injected into the wound was considered as contributing to the bursting phenomenon. There was no relation of bursting to the specific entrance wound site, type of ammunition, or projectile fragmentation.     

Lethal head injury due to tear-gas cartridge gunshots

We report a fatal head injury caused by a tear-gas cartridge and point out the underestimated potential injury of this type of weapon. Gas pressure wounds and the death mechanisms are also described. A review of the literature and forensic considerations of head injury without projectile are presented.     

Atypical Suicide by Submachine Gun

In case of suicide, the presence of multiple entrance wounds is always suspicious. We report the case of a man who committed suicide by shooting himself three times in the chest and the skull with a submachine gun. The weapon seems to have been initially pointed in the precordium area with a lethal lesion of the proximal aorta. Two other projectiles were fired by the weapon and hit the neck and the skull of the deceased. The presence of three entrance wounds despite a first fatal wound could finally be explained by the characteristics of the weapon and wounds. Most suicides related to multiple gunshot wounds are explained by a first nonlethal shot but the use of an automatic weapon can also be found. In these last cases, medicolegal and criminalistics aspects become important in differentiating suicide and homicide.     

The Difficulties in Assessing Wounds Created by .410 Bore Ammunition and Weapons

When interpreting firearm injuries, the distinction between gunshot wounds and shotgun wounds is important, and separation of these categories is typically straightforward. However, .410 bore firearms can make the classification difficult. Shotguns and revolvers that can fire the same .410 bore ammunition are readily available. This study investigates the soot and gunpowder deposits and pellet patterning of these two types of weapons using cartridges specially designed for .410 bore revolvers and standard birdshot pellet ammunition. For both ammunition types, the revolver had more prompt pellet dispersion and positive detection of gunpowder at greater distances compared to the shotgun. Additionally, .410 bore slugs are of similar caliber to many common bullets. In comparing the .410 bore slugs to equivalent bullets, some morphologic differences may be imparted on the skin by the slugs, but the greatest insight into the weapon remained with the retained projectiles.     

Fatal Injuries of Law Enforcement/Correctional Officers Attacked with Sharp‐Edged Weapons,

According to the National Law Enforcement Memorial Fund, there were 117 law enforcement fatalities in the United States in 2015. Assaults with sharp‐edged weapons have resulted in a total of over 400 fatalities in the United States. The goal of the current research was to examine sharp‐edged weapon assaults against law enforcement and correctional agents that resulted in a fatal outcome. A total of twelve autopsy reports were reviewed from across the United States. Four cases involved law enforcement officers, seven involved correctional officers, and one was an off‐duty border officer. The male‐to‐female ratio was 11:1. A total of 70.2% of the wounds analyzed were stab wounds (n = 85), and 29.8% of the wounds were slash wounds (n = 36). Based on this review, the neck, shoulder, and chest regions were the most vulnerable to single fatal stab/slash wounds. Multiple stab/slash wounds often resulted in exsanguination. The use of body armor was only noted in one case.     

Weapons used by juveniles and adult offenders in U.S. parricide cases

In recent decades, attention has focused on juveniles who kill their parents. Research has indicated that increases in juvenile homicide have been associated with the availability of firearms, but little is known about the weapons juveniles use to kill their parents and whether their weapon usage is different from that of adult children who kill their parents. This article uses Supplementary Homicide Report data for the 24-year period 1976 to 1999 to investigate weapons selected by parricide offenders to kill biological mothers and fathers. Significant differences were found in the weapons used in matricide and patricide incidents and in the weapons selected by juvenile and adult offenders. A comparison with an earlier study by Heide revealed that weapon usage in parricide events is stable. Differences found in both studies between weapons used to kill parents and offender age are consistent with a physical strength hypothesis proposed by Heide in 1993.     

Weapon Use in Korean Homicide: Differences Between Homicides Involving Sharp and Blunt Instruments

On the basis of information regarding 276 homicides committed in South Korea between 1987 and 2008, we compared offenders’ and victims’ characteristics, injury locations, weapon‐related behavior, and offending behavior between homicides involving sharp and blunt instruments. The victims of sharp‐force homicide were much younger relative to those of blunt‐force homicide. In addition, homicides involving blunt instruments were more likely to be committed by offenders who lived with the victims. Most sharp‐force homicides involved injuries to the torso, while blunt‐force homicides involved mainly head injuries. Furthermore, perpetrators of sharp‐force homicides tended to preselect their weapons, while those of blunt‐force homicides were likely to use weapons of opportunity. Logistic regression analysis identified a number of factors, including injury location and body transportation, which significantly predicted weapon type. As this was the first South Korean study to compare sharp‐ and blunt‐force homicides, the results have practical implications for homicide investigations.     

Utilizing a magnetic locator to search for buried firearms and miscellaneous weapons at a controlled research site

Forensic personnel generally use basic all-metal detectors for weapon searches because of their ease of use and cost efficiency. For ferromagnetic targets, an alternative easy to use and low-cost geophysical tool is a magnetic locator. The following study was designed to demonstrate the effectiveness of a common, commercially available magnetic locator in forensic weapon searches by determining the maximum depth of detection for 32 metallic forensic targets and testing the effects of metallic composition on detection. Maximum depth of detection was determined for 16 decommissioned street-level firearms, six pieces of assorted scrap metals, and 10 blunt or bladed weapons by burying each target at 5-cm intervals until the weapons were no longer detected. As expected, only ferromagnetic items were detected; weapons containing both ferromagnetic and nonferromagnetic components were generally detected to shallower depths. Overall, the magnetic locator can be a useful addition to weapon searches involving buried ferromagnetic weapons.     

Psychological profile of sex offenders using weapons in their crimes

Abstract

A sample of 1533 sex offenders was examined for clinical characteristics associated with weapon use in their crimes. A total of 24.9% used weapons, most often knives (50.1%), with 13.6% using multiple weapons. Weapon-users were a very disturbed group, who showed a significantly higher prevalence than non-users of psychoses, suicide attempts, alcoholism, drug addiction and abuse, personality disorders, psychopathy, attention deficit hyperactivity disorder, cognitive impairment and violent criminal histories. The weapon-users recidivated more often than non-users and appeared in court on 8.7 separate occasions compared to 2.9 for non-users in an average follow-up of 21.5 years. The best predictors of weapon use were total violent offence convictions, sadism diagnoses and adult versus child victims. The importance of examining weapon use in assessing sex offenders is discussed.     

Possibilities of spectral investigations of injuries inflicted by special arms

Quantitative characteristics and application of different spectral methods are compared in experiment. Stab and gunshot wounds were studied by roentgenospectral fluorescent and emission spectral analyses. The above spectral methods detected significant quantities of alien material on the wounds depending on the kind of the weapon.     

Suicidal shot in the mouth with a rubber shot shell

The purpose of weapons designed for self-defence and their ammunition is to allow effective defence without causing serious injury provided that the recommended minimum firing distance is observed. However, close-range and contact shots to vulnerable body regions may cause severe or even fatal injuries. The authors report on a suicide who fired a fatal shot in his mouth with a weapon for self-defence. The weapon used was a double-barrelled SAPL break-action gun, mod. GC 54, from which a Mini Gomm-Cogne, cal. 12/50 rubber shot shell was fired. The wound findings and ballistic characteristics of the weapon are presented and discussed.     

The detection of metallic residues in skin stab wounds by means of SEM-EDS: A pilot study

The morphological analysis of stab wounds may often not be accurate enough to link it with the type of wounding weapon, but a further evaluation may be performed with the search for metallic residues left during the contact between the instrument and the skin. In this study, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was applied to the study of cadaveric stab wounds performed with kitchen knives composed of iron, chromium and nickel, in order to verify the presence of metallic residues on the wound's edge. Two groups of 10 corpses were selected: group A, including victims of stab wounds and a control group B (died of natural causes). Samplings were performed on the lesions and in intact areas of group A, whereas in group B sampling were performed in non-exposed intact skin. Samples were then analysed with optical microscopy and SEM-EDS. In group A, optical microscopic analysis showed the presence of vital haemorrhagic infiltration, while SEM-EDS showed evidence of microscopic metal traces, isolated or clustered, consisting of iron, chromium and nickel. Moreover, in two cases organic residues of calcium and phosphate were detected, as a probable sign of bone lesion. Control samples (group A in intact areas and group B), were negative for the search of exogenous material to optical microscopy and SEM-EDS. The results show the utility and possible application of the SEM-EDS in theidentification of metallic residues from sharp weapons on the skin.     

Fatal neck injuries caused by blank cartridges.

We report three cases where fatal neck injuries were caused by blanks from starting pistols. The weapons were loaded with blank cartridges or tear gas cartridges. Neither live ammunition nor any form of projectile was used. All three cases involved a contact discharge. The gas pressure caused by firing the weapons created extensive wound cavities in all three cases. Each victim died from blood loss as a result of ruptured cervical vessels; there were no air embolisms. In one case, a man shot himself eight times with two different starting pistols, and the wounds could be matched to each gun by the muzzle imprint marks on the neck.