Detecting buried metallic weapons in a controlled setting using a conductivity meter

Forensic personnel may face a daunting task when searching for buried weapons at crime scenes or potential disposal sites. In particular, it is common to search for a small firearm that was discarded or buried by a perpetrator. When performing forensic searches, it is recommended to first use non-invasive methods such as geophysical instruments to minimize damage to evidence and to the crime scene. Geophysical tools are used to pinpoint small areas of interest across a scene for invasive testing, rather than digging large areas throughout the site. Prior to this project, there was no published research that tested the utility of the conductivity meter to search for metallic weapons such as firearms and blunt and sharp edged weapons. A sample comprised of 32 metallic weapons including firearms, blunt and sharp edged weapons, and scrap metals was buried in a controlled setting to test the applicability of a conductivity meter for forensic searches. Weapons were tested at multiple depths and after data collection was performed for one depth, the weapons were reburied 5 cm deeper until they were no longer detected. Variables such as weapon size, burial depth, transect interval spacing (25 and 50 cm), and metallic composition were tested. All of the controlled variables influenced maximum depth of detection. For example, size was a factor as larger weapons were detected at deeper depths compared to smaller weapons. Metal composition affected maximum depth of detection as the conductivity meter detected items comprised of ferrous metals at deeper depths than non-ferrous metals. Searches for large buried items may incorporate a transect interval spacing of 50 cm but small weapons may be undetected between transects and therefore a transect interval spacing of 25 cm is recommended. Overall, the conductivity meter is a geophysical tool to consider when searching for larger-sized metallic weapons or to use in conjunction with an all-metal detector, particularly when searching for buried metallic evidence in obstructed areas.     

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.     

Sequential monitoring of burials containing small pig cadavers using ground penetrating radar

Ground-penetrating radar (GPR) was used to monitor 12 pig burials in Florida, each of which contained a small pig cadaver. Six of the cadavers were buried in sand at a depth of 0.50-0.60 m, and the other six were buried in sand at a depth of 1.00-1.10 m to represent deep and shallow burials that are generally encountered in forensic scenarios. Four control excavations with no pig interment were also constructed as blank graves and monitored with GPR. The burials were monitored for durations of either 13 or 21 months, and were then excavated to correlate the decomposition state of the cadaver with the GPR imagery. Overall, this study demonstrated that it may be difficult to detect small cadavers buried in sand soon after they are skeletonized because the area surrounding the body, or the grave, may not provide a strong enough contrasting area to be detected by GPR when compared to that of the surrounding undisturbed soil. Also, depth of burial appears to influence grave detection because bodies that are buried at deeper depths may be detected for a longer period of time due to reduced decomposition rates.     

The Modern Compound Bow

Bows and arrows are ancient weapons that have risen and fallen as the preeminent armaments used by man. Because of the ubiquity of firearms, fatalities from archery injuries in the United States have radically declined. However, when deaths involving this weapon do present themselves, the paucity of reference materials can be a hurdle for forensic pathologists and other forensic scientists. This article will provide a brief history of the origins of the bow and the inception of the compound bow. Comparing and contrasting the structures comprising a traditional bow to those of the modern compound bow will provide insight into how these components function in unison to propel arrows.     

The Use of an Alternate Light Source for Detecting Bones Underwater

When searching underwater crime scenes or disaster scenes for fragmentary human remains, it may be advantageous for forensic divers to be able to detect the presence of bones and teeth among other marine materials (such as shells and rocks). In terrestrial environments, this can typically be accomplished by visual and instrumental methods, but underwater conditions make it difficult to employ detection and sorting techniques in these environments. This study investigates fluorescence of bones and teeth and other marine materials using a submersible alternate light source (ALS) and concludes that an ALS can be a useful tool for detecting bones and teeth in underwater searches as well in terrestrial searches and laboratory environments. The results could impact the methods and equipment used by forensic divers and forensic anthropologists when searching for skeletal remains, potentially increasing the quantity and efficiency of forensic evidence recovered.     

Suicidal Shotgun Wound Employing a Shotgun Barrel,a Shotgun Shell,and a BB*

Abstract: A vast majority of firearms‐related suicides involve the conventional use of a properly functioning, intact firearm. Occasionally, forensic investigators encounter a case wherein the firearm suicide victim employs some form of unconventional use of a weapon, or utilizes an unusual weapon type. In this case report, the authors present an unusual case in which a man committed suicide by using a shotgun shell, a shotgun barrel (separate from the rest of the gun), and a BB. Some confusion as to the cause and manner of death was present during the initial scene investigation. Examination at autopsy revealed the cause of death to be a shotgun wound of the chest and prompted further scene investigation. Therefore, this case serves as another example of the importance of cooperation between scene investigators and forensic pathologists when investigating a death. A review of suicidal firearm cases using unconventional means and/or firearms is presented.     

Macroscopic characteristics of hacking trauma

Hacking trauma is often encountered in forensic cases, but little experimental research has been conducted that would allow for the recognition of wounds caused by specific weapon types. In this paper, we report the results of a hacking trauma caused by machete, cleaver, and axe weapons and the characteristics of each weapon type on bone. Each weapon type was employed in multiple trials on pig (Sus scrofa) bones and then the wounds were examined macroscopically for several characteristics that serve to differentiate the weapons.     

Geophysics and the search of freshwater bodies: A review

Geophysics may assist scent dogs and divers in the search of water bodies for human and animal remains, contraband, weapons and explosives by surveying large areas rapidly and identifying targets or environmental hazards. The most commonly applied methods are described and evaluated for forensic searches. Seismic reflection or refraction and CHIRPS are useful for deep, open water bodies and identifying large targets, yet limited in streams and ponds. The use of ground penetrating radar (GPR) on water (WPR) is of limited use in deep waters (over 20 m) but is advantageous in the search for non-metallic targets in small ditches and ponds. Large metal or metal-bearing targets can be successfully imaged in deep waters by using towfish magnetometers: in shallow waters such a towfish cannot be used, so a non-metalliferous boat can carry a terrestrial magnetometer. Each device has its uses, depending on the target and location: unknown target make-up (e.g. a homicide victim with or without a metal object) may be best located using a range of methods (the multi-proxy approach), depending on water depth. Geophysics may not definitively find the target, but can provide areas for elimination and detailed search by dogs and divers, saving time and effort.     

Penetration Depth of Projectiles Fired from a Replica of Colt Navy of 1851 in 20% Gelatin Blocks Correlated with Fatal Injuries Assessed in an Autopsy of a 78‐Year‐Old Man

Pursuant to the Polish Weapons and Ammunitions Law, muzzle‐loading black powder weapons, manufactured before 1885, or their replicas, as well as suitable projectiles, can be possessed legally without registration and special licenses. The aim of the study was to assess the penetration depth of projectiles fired from a black powder weapon, replica of Colt Navy of 1851, in 20% gelatin blocks and to compare the obtained results with the actual injuries found on autopsy of a 78‐year‐old man who had committed suicide. In the experiments, we used the black powder weapon and ammunitions, as well as gelatin blocks serving as a soft tissue model. We ascertained that solid spherical projectiles fired from black powder weapons cause extensive injuries, especially in the initial segment of the wound canal. Additionally, based on the presence and location of the wad in the wound canal, the distance from which the shot was fired can be determined.     

Identification of a Carbonized Body Using Implanted Surgical Plates: The Importance of Computed Tomography

In addition to clinical examination, forensic odontologists can use diagnostic imaging as an auxiliary method for identification. This paper reports a case where forensic odontologists from the Afrânio Peixoto Legal Medicine Institute in Rio de Janeiro (Brazil) positively identified a carbonized and partially calcined body using oral and maxillofacial imaging. The cadaver showed several metallic plates fixed with metallic screws on bones of the neurocranium and viscerocranium. Family members provided spiral computed tomography scans of the skull and a panoramic radiograph that were acquired after an accident that required surgical procedures. Comparative analysis between the clinical exam and the maxillofacial images demonstrated complete coincidence, confirming the victim's identity. Dactyloscopy, which is the most commonly used method of identification, was not possible because of the body carbonization. Thus, diagnostic imaging, especially computed tomography, was essential for elucidation of this case.     

磁珠直接吸附法对体态检材游离DNA的提取

目的采用磁珠直接吸附法对人体尿液、唾液、血液3种体态生物检材中的游离DNA进行提取检验,为法医物证中游离DNA的研究及检验工作提供参考。方法对3种生物检材采取离心吸取上清液的方法分离游离DNA,然后采用磁珠直接吸附法进行提取纯化,Identifiler-Plus试剂盒进行复合扩增后常规STR检测。结果在3种检材中均检出了游离DNA,其中血液中游离DNA检出率为100%,唾液为90%,尿液为70%。结论人体体态生物检材中存在游离DNA,同时磁珠直接吸附法可高效、快捷的提取生物检材中的游离DNA。     

The Reconstruction of the Dynamic of a Murder Using 3D Motion Capture and 3D Model Buildings: The Investigation of a Dubious Forensic Case

Photographic surveying is fundamental to crime scene investigation. It is performed using 2D images; however, this method is limited because it does not offer a detailed view. We present a 3D (three‐dimensional) experimental model that has clarified unsolved aspects of a homicide. A woman was found dead in her home. Considering the large number of injuries on the victim, signs of the use of two weapons, and the absence of traces of the killer/s, several hypotheses about the dynamics and the number of offenders were made. The forensic surveys suggested that a single offender had used two weapons at the same time, but this hypothesis was considered to be impossible by investigators. Our 3D model allowed us to experimentally reproduce the murder and compare various dynamics. The model was used as evidence in Court to prove the hypothesis of a single killer and demonstrate that no other people were involved.     

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.     

Piercing the surface: A mechanical analysis of stabbing with household tools

Estimating the applied power during a stabbing incident, or estimating the minimal force necessary to penetrate the body with a certain weapon is a challenging task in forensic practice. A thorough forensic evaluation of stabbing forces needs objective numerical experimental data. Stabbing tests of 12 different weapons – including knives, a pair of scissors, a fork, screwdrivers, a rasp, a corkscrew, and a utility knife blade – were performed with a Mecmesin MultiTest-dV material tester on pork loin and ballistic gel to estimate the stabbing forces and dynamics. Penetration force (F_p) and maximal force (F_max) were recorded, and the registered force curves were analyzed. F_max was 159.8–212.07 Newton (N), 30.56–30.58 N, 168.9–185.48 N for various knives; 171.39–190.43 N for the pair of scissors, 233.6 N for the fork; 532.65–562.65 N, 370.31–367.19 N and 314.51–432.89 N for various screwdrivers, 44.14–56.62 N for utility knife during pork loin stabbing. The butter knife, corkscrew and rasp were not able to penetrate the pork loin, and the curved fork bent during stabbing. The results prove that weapon characteristics greatly influence the force necessary for penetration. Maximal stabbing force depends mostly on tip sharpness, and the force sharply decreases after penetration occurs, which indicates that edge sharpness is not as important as tip characteristics during stabbing perpendicular to skin surface. The penetration force during stabbing with a pair of scissors is comparable to the penetration force of knives. Stabbing with screwdrivers generally needs larger force than average knives but depends greatly on screwdriver size.     

Introducing 3D Printed Models as Demonstrative Evidence at Criminal Trials

This case report presents one of the first reported uses of a 3D printed exhibit in an English homicide trial, in which two defendants were accused of beating their victim to death. The investigation of this crime included a micro‐CT scan of the victim's skull, which assisted the pathologist to determine the circumstances of the assault, in particular regarding the number of assault weapons and perpetrators. The scan showed two distinct injury shapes, suggesting the use of either two weapons or a single weapon with geometrically distinct surfaces. It subsequently served as the basis for a 3D print, which was shown in court in one of the first examples that 3D printed physical models have been introduced as evidence in a criminal trial in the United Kingdom. This paper presents the decision‐making process of whether to use 3D printed evidence or not.     

Investigation of the variability in the tool marks produced by modified blank firing pistols on fired 7.65 mm projectiles

Firearms identification has an important place in forensic ballistic investigations since the weapons are widely used in criminal offences. Firearm examiners resolve many case files, through the use of automatic systems or comparison microscopes. Advanced forensic technologies like BALİSTİKA helps to record and analyze non standard ballistic evidence. In today's world, with the ease of access to materials and production technique information, pistols modified from blank firers are frequently encountered as crime tools. In this study, the characteristics of 7.65 mm fired cartridge cases obtained by controlled shots from blank firing modified pistols were examined, and their detection performances were compared by means of the Balistika system. Although distinctive differences are not expected after successive test shootings, balistically important changes were seen after the use of blank firing modified pistols and the 3D imaging system proved to be useful in observing such differences. The analyses showed that the modifications in weapons lead to variation in the ballistic characteristics and reduce the accuracy of the detection performance, which may result in flawed forensic decisions. It was also found that the deviations in ballistic impressions of modified blank firing pistols were greater than that of standard fabricated and hand-made pistols. This unique study contributed to the forensic sciences literature by focusing on the impact of modified weapons on ballistic characteristics.     

Suicide with a walking cane gun: weapon, injury picture and psychopathology]

In Germany firearms camouflaged as items of daily use are forbidden. While reports on ball-point pen-guns have repeatedly been published in literature, the use of a walking-stick gun is a rarity. The report deals with the suicide of a 31-year-old schizophrenic man who inflicted a shotgun injury to his head with typical morphological characteristics. The weapon used was a normal-looking walking stick with a barrel, cal. .410. Under forensic and criminological aspects the significance of a walking-stick gun is comparable to that of ball-point pen-guns. Both weapons can be carried and used inconspicuously, but from a walking-stick gun also ammunition of larger calibres with a higher potential of injury can be fired.     

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.     

An atypical gunshot wound from a home-made zip gun--the value of a thorough scene investigation

Zip guns and the atypical gunshot wounds they produce are rare in forensic pathology. Because of this, investigators and forensic pathologists may be unfamiliar with their construction, appearance, and the wounds associated with them. A 43-year-old mechanic, with a history of depression was found dead in a washroom stall at work with an atypical gunshot wound of the head. Upon initial investigation, no weapon was found at the scene. Due to the nature of the scene, and the unusual characteristics of the wound, the manner of death was at first thought to be a homicide. Subsequently, a simple zip gun, which had been overlooked during the scene investigation, was discovered by a co-worker while he was cleaning the stall. Examination of the wound revealed evidence of contact range firing. A markedly deformed bullet was recovered from the head, consistent with the use of the home-made gun. These findings, along with further police investigation and review of the past medical history, indicated that the manner of death was a suicide.     

Increasing Allele Detection by Altering the Quantity of Internal Lane Standard

Electrokinetic injection (EI) is the primary method used in forensic laboratories to load amplified PCR product in capillary electrophoresis for short tandem repeat (STR) fragment separation. Because all samples subjected to capillary electrophoresis use internal lane standard (ILS), this study investigated the consequence of varying the volume of ILS and its effects on allele peak heights and number of alleles detected. Results demonstrated that when the volume of ILS is reduced, the average peak height and number of alleles increased, thereby increasing the sensitivity of the detection method. Sizing anomalies were observed; however, they did not adversely affect accuracy and precision. The method developed in this study offers a simple and universal procedure to increase the alleles detected in forensic STR analysis. Reducing the volume of ILS to achieve greater sensitivity is applicable to all STR amplification kits and capillary electrophoresis instruments currently used in forensic DNA analysis.