2,4,6-Tri(2′-pyridyl)-1,3,5-triazine for determination of iron(II), Iron(III), and total iron contents on human palms

When iron-based tools, such as knives or guns, are held, traces of iron can transfer to the skin. However, no previous studies have been published regarding the effect of the elapsed contact time on the transfer of iron species with different valences to the palm. Compared with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT), 2,4,6-tri(2′-pyridyl)-1,3,5-triazine (TPTZ) was found to exhibit a higher sensitivity to iron(II) spectrophotometrically. This work employed 2,4,6-tri(2′-pyridyl)-1,3,5-triazine (TPTZ) and UV spectrophotometry to determine the amounts of iron(II), iron(III), and total iron transferred to human palms from iron tools. It was found that the palmar moisture level was an important factor in determining the amounts of total iron, including iron(II), transferred to the palm. For identical contact times, the amounts of total iron transferred to the palm was proportional to the palmar moisture, and the difference between the maximum and minimum amounts was 12 μg per hand. However, the amounts of iron(II) transferred to the palm gradually decreased over time for low palmar moisture levels, but steadily increased over time for high palmar moisture levels. Additionally, for average levels of palm moisture, the amounts of iron(II) and iron(III) transferred to the palm gradually decreased and increased, respectively, with longer contact times. Notably, this research could serve as a theoretical basis and guide for the detection of trace iron species with different valences on human palms for criminal investigations.     

Secondary transfer of organic gunshot residues: Empirical data to assist the evaluation of three scenarios

The present study aimed at providing data to assess the secondary transfer of organic gunshot residues (OGSR). Three scenarios were evaluated in controlled conditions, namely displacing a firearm from point A to point B, a simple handshake and an arrest involving handcuffing on the ground. Specimens were collected from the firearm, the hands of the shooter and the non-shooter undergoing the secondary transfer in order to compare the amounts detected.Secondary transfer was observed for the three scenarios, but to a different extent. It was found that displacing a firearm resulted in secondary transfer in <50% of the experiments. The firearm also had an influence, as contrary to the pistol, no secondary OGSR were detected using the revolver. Shaking the hand of the shooter also transferred OGSR to the non-shooter's hand. In that case, the amount of OGSR was generally higher on the shooter than on the non-shooter. Finally, the largest secondary transfer was observed after the arrest with handcuffing with positive results in all cases using the pistol. In that scenario, the amounts on the shooter and the non-shooter were in the same range.This study highlights that the secondary transfer must be taken into account in the interpretation of OGSR. Indeed, an individual's hands might be contaminated by handling a firearm or having physical contact with a shooter.     

Sex Determination from Hand Dimensions of North and South Indians

Abstract:  When dismembered human remains are encountered, the decedent's sex may not be obvious. For these scenarios, techniques for sex determination may play a vital part of the medicolegal investigation. Five hundred hands (230 males, 270 females) from North and South Indian region were studied to investigate sexual dimorphism in hand dimensions (hand length, hand breadth, and palm length). The hand index (hand breadth/hand length × 100) and the palm index (hand breadth/palm length × 100) were derived. The hand dimensions show a higher accuracy in sex determination when compared to indices. Of all hand dimensions, hand breadth has the highest accuracy of sex determination in the study group. The sex differences were found to be statistically significant only for the hand index on the left side. The morphometric parameters of the hand show considerable sexual dimorphism in the Indian population while the hand and palm index remain poor sex indicators. The study thus has medicolegal implications when a dismembered hand is brought for examination.     

Transfer of Triazine‐iron(II) Chromic Complexes Left by Iron Items on Textile Background and Human Skin

Abstract: The research is focused on the detection and transfer of iron traces left by iron items on clothing and human skin. The method is based on the formation of colored complexes between ferrous ions and five synthesized, mostly new triazines. Iron traces originally were left by iron rings on slightly wetted (artificial sweat) cotton fabrics and subsequently transferred to a separate textile substrate. Prior to the use of trazines the contact spots were treated with a new inorganic reducing agent (Sn²⁺) to reduce Fe³⁺ to Fe²⁺. The method is sensitive to detect iron traces on wetted canvas after 10 min contact with iron items. More spectacular results were obtained for traces left on human palm even after very short contact (10 sec). The new iron‐trace‐transfer method eliminated the contact of triazines solutions with human skin. Transmission visible spectra of Fe(II)–triazine complexes were determined.     

A singular case of murder-suicide committed with a homemade firearm

The authors illustrate a peculiar case of murder-suicide committed with a homemade firearm loaded with 12-gauge cartridges (buckshot). The structure and function of this handcrafted firearm were simple but effective: an iron tube did duty as a barrel in this primitive firearm. The cartridges (modified by winding sticky tape around the external surface of the base) were inserted down one end of the tube (serving as the breech). A second iron tube with a larger diameter (so as to be able to run over each of the preloaded barrels) and with a jutting, cone-shaped metal wedge soldered to the base, was used as a rudimental firing pin. After loading the "barrel" with the modified cartridge, the gunman would ram the "firing pin" tube violently down to fire the shot. Autopsy of the woman's body showed the presence of 3 gunshot wounds caused by buckshot, while the man had a single buckshot wound in the head. Subsequent ballistic investigations enabled reconstruction of the event (typical of murder-suicide) and the functioning of the firearm, demonstrating its lethal nature, remarkably easy handling, and simplicity of production.     

A model for estimating the number of glass fragments transferred when breaking a pane: experiments with firearms and hammer.

Numerous publications have shown the importance of transfer in the interpretation of glass evidence. As this phenomenon is also highly variable, it was decided to test the hypothesis that there exists a means to predict the number of fragments recovered at time t = 0. Panes of float glass-of different types and thickness-were broken using either a firearm or a hammer. It was decided to choose a firearm as the main breaking device, as it allowed not only to have more reproducible conditions but also to acquire knowledge in a field where little has been published. Despite the inherent variation in the breaking process, the results show that using a statistical model it is possible to predict the number of fragments transferred onto a garment from the number of fragments transferred to the ground. This research also indicates the size and number of particles transferred onto a person, when breaking window panes of different types (float, laminated or toughened) with different breaking procedures.     

Comparison of GSR Composition Occurring at Different Locations Around the Firing Position

Abstract: Variations in gunshot residue (GSR) compositions are used in the reconstruction of shooting incidents. In this study, GSR samples taken from seven different locations around and in the firearm were collected and analyzed using scanning electron microscopy/energy dispersive X‐ray analysis. Four different types of ammunition were applied. Very low correlations were found when different ammunition were used. This clearly shows that it is possible to differentiate between ammunition types. When the same ammunition was used, high correlations were found between samples taken from external positions (such as hands of shooter, bullet‐entrance holes) but poor correlation was found between internal samples (such as firearm barrel, cartridge case) and external samples. A high degree of association was found between samples that simulated victim and shooter. These findings clearly demonstrate that GSR comparison studies are meaningful but care needs to be taken when choosing suitable exhibits. External samples (such as hands of shooter, bullet‐entrance holes) are more suitable candidates than internal samples (barrel of the firearm, cartridge case).     

Distribution of GSR particles in the surroundings of shooting pistol

Several series of experiments were performed to study the distribution of GSR particles in seven directions in the surroundings of shooting firearm (pistol CZ 85 caliber 9 mm Luger). External and internal conditions and two different primer types were used for the shooting experiments. The results showed that maximum number of GSR particles could be found in the right front quadrant at a distance of 2–4 m with respect to the shooting firearm position and shooting direction. GSR particles were even found in distance 10 m from shooting firearm. A significant influence of climatic conditions on GSR distribution was confirmed.     

Identification of a Buried Cadaver Based on Finger Ridge Characteristics of a Hand Protected by a Latex Glove

This paper presents the case of a cadaver buried in a pine grove, in loamy soil at a depth of about 1.8 m. The case is quite interesting due to the fact that one hand of the victim was bare and the other one was clad in a latex glove. In the laboratory, the severed hands were gently washed with water. The left palm exhibited signs of advanced decomposition. The ridges were visible only on the thumb. The gloved hand was found to be in much better condition. There were signs of saponification on the palm. Ridges on both the palm and all fingers were visible. The fingers of the right hand, palm prints, and the thumb of the left hand were successfully matched against a ten-print card. The match provided the police with a positive identification of the missing person.     

Estimation of stature from hand impression: a nonconventional approach

Stature is used for constructing a biological profile that assists with the identification of an individual. So far, little attention has been paid to the fact that stature can be estimated from hand impressions left at scene of crime. The present study based on practical observations adopted a new methodology of measuring hand length from the depressed area between hypothenar and thenar region on the proximal surface of the palm. Stature and bilateral hand impressions were obtained from 503 men of central India. Seventeen dimensions of hand were measured on the impression. Linear regression equations derived showed hand length followed by palm length are best estimates of stature. Testing the practical utility of the suggested method on latent prints of 137 subjects, a statistically insignificant result was obtained when known and estimated stature derived from latent prints was compared. The suggested approach points to a strong possibility of its usage in crime scene investigation, albeit the fact that validation studies in real-life scenarios are performed.     

Shotgun shooting in northern India--a review (1980-1999)

Central Forensic Science Laboratory (CFSL), Chandigarh undertakes the examination of the crime cases of some northern states of India. The shooting cases of last two decades (1980-1999) involving shotguns were analysed in this laboratory. This paper consists of the study of 360 actual cases of shotguns for evaluation of various parameters, such as type of firearm, number of firearm and firing, location of wound, age, occupation, sex and caste of accused and victim, etc. Out of 360 cases, 253 (70%) were classified as homicidal, 68 (19%) accidental, 11 (3%) suicidal, 9 (2.5%) hunting and 19 (5.5%) cases of insufficient information including the cases of illegal possession of firearm. Single Barrel Breech Loading (SBBL) gun 144 (40%) was preferred over Single Barrel Muzzle Loading (SBML) 109 (30.3%), Double Barrel Breech Loading (DBBL) 72 (20%) and Double Barrel Muzzle Loading (DBML) gun 35 (9.7%). All the breechloader guns were of 12 bore. Muzzleloader gun were recovered only from the remote rural areas. Three hundred and thirty-one (92%) cases involved single, 22 (6%) double and 7 (2%) more than two shotgun. Majority of cases were found of single firing 288 (80%), followed by double 29 (8%) and multi-firing 18 (5%). Eleven (3%) cases were of misfiring and in 14 (4%) cases information was not available. Accidental and suicidal cases had only one firing. The mean age for male and female victim was 31 and 24 years, respectively. Occupationally, agriculture is predominating over business, service and security guards for accused and for victim agriculture followed by service, business, student and security guards are in the descending order. Caste wise the most aggressive community of Kshatriyas is predominating as accused and victim over lower cast people. Head (64%) being a vital part was chosen most frequently for committing suicide followed by body (36%). Service personnel committed maximum number of suicide.     

Close proximity gunshot residues

Intuitively, a hand held in close proximity to a firearm at the instant of discharge will intercept a significant amount of gunshot residue, even though the hand did not actually come into contact with the weapon. There is, however, little information specifically described in the forensic science literature concerning the residue levels which might be encountered in such an instance. The present work confirms that antimony levels consistent with an individual having fired or handled a firearm may be intercepted by a hand held in close proximity.     

Gunshot residue testing in suicides: Part I: Analysis by scanning electron microscopy with energy-dispersive X-ray

Several different methods can be employed to test for gunshot residue (GSR) on a deceased person's hands, including scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each of these techniques has been extensively studied, especially on living individuals. The current studies (Part I and Part II) were designed to compare the use and utility of the different GSR testing techniques in a medical examiner setting. In Part I, the hands of deceased persons who died from undisputed suicidal handgun wounds were tested for GSR by SEM-EDX over a 4-year period. A total of 116 cases were studied and analyzed for caliber of weapon, proximity of wound, and results of GSR testing, including spatial deposition upon the hands. It was found that in only 50% of cases with a known self-inflicted gunshot wound was SEM-EDX positive for at least 1 specific particle for GSR. In 18% of the cases there was a discernible pattern (spatial distribution) of the particles on the hand such that the manner in which the weapon was held could be determined. Since only 50% of cases where the person is known to have fired a weapon immediately prior to death were positive for GSR by SEM-EDX, this test should not be relied upon to determine whether a deceased individual has discharged a firearm. Furthermore, in only 18% of cases was a discernible pattern present indicating how the firearm was held. The low sensitivity, along with the low percentage of cases with a discernible pattern, limits the usefulness of GSR test results by SEM-EDX in differentiating self-inflicted from non-self-inflicted wounds.     

Classification of firing pin impressions using HOG-SVM

Crimes, such as robbery and murder, often involve firearms. In order to assist with the investigation into the crime, firearm examiners are asked to determine whether cartridge cases found at a crime scene had been fired from a suspect's firearm. This examination is based on a comparison of the marks left on the surfaces of cartridge cases. Firing pin impressions can be one of the most commonly used of these marks. In this study, a total of nine Ruger model 10/22 semiautomatic rifles were used. Fifty cartridges were fired from each rifle. The cartridge cases were collected, and each firing pin impression was then cast and photographed using a comparison microscope. In this paper, we will describe how one may use a computer vision algorithm, the Histogram of Orientated Gradient (HOG), and a machine learning method, Support Vector Machines (SVMs), to classify images of firing pin impressions. Our method achieved a reasonably high accuracy at 93%. This can be used to associate a firearm with a cartridge case recovered from a scene. We also compared our method with other feature extraction algorithms. The comparison results showed that the HOG-SVM method had the highest performance in this classification task.     

Weapon location following suicidal gunshot wounds

The location of the gun following suicidal gunshot wound was studied by reviewing 574 such deaths in which the scene was investigated by a medical examiner investigator and the body was examined at the Bexar County Medical Examiner's Office in San Antonio, Texas. The position of the gun could not be established in 76 cases. In the remaining 498 cases, the gun remained in the deceased's hand in 24% of the cases. In 69% of the cases, the gun was on or near the body but not in the hand (i.e., touching the body or within 30 cm of the body). The gun was found >30 cm from the body in the remaining 7% of cases. In the case of handguns, the gun was found in the hand in 25.7% of individuals. For individuals using long guns, the firearm was in the hand of the decedent in 19.5% of cases. The gun had a greater chance of remaining in the deceased's hand if the person was lying or sitting when the gunshot wound was received. Variables such as gender of the individual, wound location, and caliber of handgun were not significant in predicting whether the gun stayed in the hand after a suicidal gunshot wound.     

Suicide,accident? The importance of the scene investigation

We present the as yet unresolved case of the death by gunshot wound of a 21-year-old student from a recent local inspection. It was reported that the daughter of the house had been shot through the window while she was washing the dishes. Slight discrepancies were noted in the statements of the family, who are very religious. The firearm, projectile and cartridge have not been found despite an intensive search. The daughter and the mother tested positive for traces of gunpowder on their hands, while in the case of the son traces were found on his hands and on his vest. That the trajectory of the projectile was from the kitchen outwards was established on the basis of a small hole in the inner pane of the kitchen window and a larger hole in the outer pane. The shot passed through the victim's cheek and the neck. The entrance wound (aditus) on the right cheek had complementary features characteristic of a gunshot from a short-barrelled firearm at relative proximity. The shot passed through the left jugular vein and the left internal carotid artery. The exit wound (exitus) was slightly larger and of irregular shape.The family chose a traditional burial. The mother and son did not present themselves for polygraph testing. A charge was filed against the mother of the deceased. Emphasis was placed on the scene investigation.A covered-up suicide? An accident (a scuffle when trying to prevent suicide)?     

丢失枪支不报罪的立法缺陷与完善

对丢失枪支不报罪立法设计上的缺陷及其完善问题,从罪状、法定刑与法理三个层面上作了一定程度的探讨,建 议将该条修改为:依法配备、配置枪支的人员,在枪支丢失、被盗、被抢或者被骗后不及时报告的,处三年以下有期 徒刑或者拘役;造成严重后果的,处三年以上七年以下有期徒刑。     

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.     

Armed Americans: The impact of firearm availability on national homicide rates

This study examines the relationship between firearm availability and national homicide rates. The theoretical and empirical literatures are reviewed, and a cross-national two-stage least squares regression analysis is described. The relationship between a circa 1990 measure of firearm availability and the average 1990–1994 homicide rate is examined across 36 countries. Two-stage least squares regression, which controls for homicide's effect on firearm availability in addition to a number of other confounding factors, reveals a statistically significant positive effect of firearm availability on national homicide rates. The magnitude of the association is considerable. The observed relationship is found to be insensitive to sample composition. Results also indicate that homicide rates do not influence levels of firearm availability. The limitations of the study and avenues for future research are discussed.     

Firearm Ownership in High-Conflict Families: Differences According to State Laws Restricting Firearms to Misdemeanor Crimes of Domestic Violence Offenders

This study examines the association between state laws that prohibit firearm ownership for offenders convicted of misdemeanor crimes of domestic violence (MCDV) and firearm ownership in two-parent families with high-conflict male partners with arrest histories. Mixed effects logistic regression models applied to data from the Early Childhood Longitudinal Study-Birth cohort (n?= 5350) determined that living in a state with laws that prohibited firearm ownership for convicted MCDV offenders decreased the likelihood of firearm ownership among families with high-conflict males by 62%. The length of the time limit on firearm prohibition was correlated with incremental decreases in firearm ownership in such families, with the probability of firearm ownership among families with high-conflict males decreasing from 30% in states with no MCDV laws restricting access from firearms to 12% in states with permanent prohibition on firearm ownership. These findings have significance for public health policy aimed at decreasing intimate-partner homicide.