Time since discharge of pistols and revolvers

The estimation of time since the latest discharge of pistols and revolvers has been achieved by the Solid Phase Microextraction (SPME) sampling technique and the GC/TEA analytical system. The TEA2 compound, which in our previous work (1) was observed in barrels of shotguns and rifles as well as inside spent cartridges, was also detected in pistols and revolvers. The amount of this compound was very low in short-barreled small arms and its escape from the barrel could generally be measured for only a few days or up to two weeks after the latest discharge. To improve the detection of TEA2 compound, the SPME sampling time was prolonged and fibers coated by Carboxen/polydimethylsiloxane were used. The decrease of the TEA2 peak with time after shooting from pistols is nonexponential but the curve-fitting procedure proposed for the estimation of time since discharge of shotguns and rifles is difficult to apply as the decay is very rapid. Therefore, the detection of TEA2 compounds in small arms should be interpreted that the firearm had been used very recently. The amount of volatile decomposition products of smokeless powder increased significantly with the length of the barrel when firearms of the same caliber, but with different barrel lengths were investigated.     

Unusual sources of Sn in GSR. An experimental study by SEM and IBA

Gunshot Residue (GSR) produced by the discharge of a firearm often provides very useful information in criminal investigations in cases involving the use of firearms. Scanning Electron Microscopy equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDS) is typically used worldwide to visualize micrometric particles constituting GSR and to analyse their elemental composition. The 2017 ASTM Standard guide for gunshot residue analysis by scanning electron microscopy/energy dispersive X-ray spectroscopy specifies that “Particles classified as characteristic of GSR will have one of the following elemental compositions: Lead, antimony, barium; Lead, barium, calcium, silicon, tin”. For the first time, the presence of an additional element, such as Sn, plays a key role in ASTM particle classification. It is known that some ammunitions, used for pistols, revolvers and rifles, contain tin foil discs for sealing the primer mixture into the cup, resulting in GSR particles containing Sn. The authors faced some cases in which Sn was unexpectedly found in GSR particles from a 0.22 Long Rifle derringer and from some 12 gauge shotguns. No tin foil discs are used in rimfire ammunitions and there is no published evidence of tin foil discs in shotshell ammunitions. Following a “case by case” approach, experimental research has been carried out to explain how Sn can be present in GSR particles when the last discharged cartridge also does not contain any Sn either in components and in the explosive charges.Moreover, the use of Particle Induced X-ray Emission (PIXE) showed the capability to overcome overlap ambiguity of Sb and Sn peaks in the X-ray spectra, being a possible key issue in real shooting cases if Sn quantities are below the lower limit of SEM detection, especially when Sb is also present.     

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.     

Canadian firearms legislation and effects on homicide 1974 to 2008

Canada has implemented legislation covering all firearms since 1977 and presents a model to examine incremental firearms control. The effect of legislation on homicide by firearm and the subcategory, spousal homicide, is controversial and has not been well studied to date. Legislative effects on homicide and spousal homicide were analyzed using data obtained from Statistics Canada from 1974 to 2008. Three statistical methods were applied to search for any associated effects of firearms legislation. Interrupted time series regression, ARIMA, and Joinpoint analysis were performed. Neither were any significant beneficial associations between firearms legislation and homicide or spousal homicide rates found after the passage of three Acts by the Canadian Parliament--Bill C-51 (1977), C-17 (1991), and C-68 (1995)--nor were effects found after the implementation of licensing in 2001 and the registration of rifles and shotguns in 2003. After the passage of C-68, a decrease in the rate of the decline of homicide by firearm was found by interrupted regression. Joinpoint analysis also found an increasing trend in homicide by firearm rate post the enactment of the licensing portion of C-68. Other factors found to be associated with homicide rates were median age, unemployment, immigration rates, percentage of population in low-income bracket, Gini index of income equality, population per police officer, and incarceration rate. This study failed to demonstrate a beneficial association between legislation and firearm homicide rates between 1974 and 2008.     

Estimating the time since discharge of spent cartridges: A logical approach for interpreting the evidence

Estimating the time since discharge of a spent cartridge or a firearm can be useful in criminal situations involving firearms. The analysis of volatile gunshot residue remaining after shooting using solid-phase microextraction (SPME) followed by gas chromatography (GC) was proposed to meet this objective. However, current interpretative models suffer from several conceptual drawbacks which render them inadequate to assess the evidential value of a given measurement. This paper aims to fill this gap by proposing a logical approach based on the assessment of likelihood ratios. A probabilistic model was thus developed and applied to a hypothetical scenario where alternative hypotheses about the discharge time of a spent cartridge found on a crime scene were forwarded. In order to estimate the parameters required to implement this solution, a non-linear regression model was proposed and applied to real published data. The proposed approach proved to be a valuable method for interpreting aging-related data.     

Distribution of gunshot residues--the influence of weapon type

Gunshot residue (GSR) analysis is a frequently used forensic method for investigating shooting events. In this process, GSR-particles are detected on pertinent objects, often the hands of a suspect, with energy dispersive X-ray microanalysis in a scanning electron microscope. The question asked in court is usually the following: "… has or has not a given shot been fired by the suspect (at a certain place and time)?" Unfortunately, this question frequently cannot be answered by the analyst. Only the presence or absence of "characteristic" GSR-particles on the investigated sample can be stated with confidence. All other assumptions are inherently biased by many factors that are usually only known by the culprit or are generally unknown. In order to draw more profound conclusions from GSR analytical results, the dynamics of GSR particles have to be considered, i.e., how these particles reach a suspect. Consequently, the formation of the plume after firing was investigated for eleven different firearms with high speed-video analysis. The results show that a vast scope exists between revolvers - distributing many particles near the shooter - and e.g. shotguns that are quite sealed. These differences between the various weapon types should be considered for interpretation of the results of GSR-analysis.     

Time since discharge of shotgun shells

A technique for the estimation of time since discharge of a given class of spent shotgun shells is presented. The technique involved the use of SPME (Solid Phase Microextraction) sampling from the atmosphere inside spent shotgun shells. Compounds absorbed on the SPME fiber were desorbed and analyzed with GC-MS. The decrease in concentration of the combustion product naphthalene was monitored in all shells over a two-month period. Three conditions were examined to prevent naphthalene from escaping prior to testing the shells. A glass vial was successfully incorporated to halt the dissipation of naphthalene. At room temperature the naphthalene peak can be measured for several months and the curve-fitting data can lead to an estimation of time since discharge.     

Firing distance estimates with pellet dispersion from shotgun with various chokes: an experimental, comparative study

There are several studies suggesting models for firing distance estimation due to pellet dispersion, but few of them consider the degree of choke of a shotgun. The purpose of this research is to suggest some models for estimation of the firing distance for choked and cylinder bore shotguns. Twelve gauge with full chokes, and 12 and 16 gauge with cylinder bore shotguns were fired with #2 and #5 shots from 75, 100, 300, 500, and 1000 cm distances. Statistically significant pellet dispersion values were found for each shotgun by using #2 and #5 shots for different firing distances. All the data obtained were analyzed with linear regression and four models were constituted. Investigators should use special formulae for each shotgun, degree of choke, and pellet type while determining the firing distance. Therefore, more experimental and comparative studies should be designed for each type.     

Suicide by firearms: a 15-year experience.

A retrospective review of 1704 cases of suicide involving firearms investigated by the Bexar County Medical Examiner's office between 1984 and 1998 was performed. The age distribution was similar in male and female victims, and the type of weapon was not associated with age. Approximately 78% of the victims used a handgun (87% of female and 76% of male victims). In 4.0% of head wound cases, the site of the entrance wound was the back of the head. Thus, this report refutes the common belief that all gunshot wounds to the back of the head represent homicides. In 1.9% of the cases, the wounds were inflicted at intermediate range. With handguns, the right temple was the most common site, but with rifles and shotguns, the most common site was the mouth.     

Fatal firearm accidents in Sweden

According to Swedish law, it is prohibited to possess and use firearms without a special permission (license), which is given only after a detailed personal investigation. This restrictive legislation accounts for the fact that deaths due to firearms in Sweden are rare in an international comparison. The number of accidental firearm fatalities in Sweden is 0.074/100,000 living persons. We have previously published a series of accidental firearm fatalities during hunting, and now we present an investigation on the non-hunting fatalities. The mean age of the victims was 27 years, and males predominated. Handguns, military rifles, and shotguns caused most of the accidents. The first published case of fatal thoracic airgun wound is also included. Slightly more than half of the accidents were caused by another person and were inflicted at close range. Unsafe handling of the guns, especially "playing" with the gun or during military training caused most of the accidents. It is doubtful that one could further decrease the low number of fatal firearm accidents in Sweden by even more restrictive legislation. Instead, it is concluded that the most important factor to stress is the safer handling of weapons.     

论标题的知识产权保护

现代知识产权制度是个有机整体。标题可能受到版权法、商标法和反不正当竞争法的保护。一般而言，标题可版权性的要件是原创性，并且不是普通的、惯用的词汇；单个作品的标题不能够获得商标法保护，丛书的标题则在满足一定条件的情况下受到商标法保护；当标题获得第二含义，并且被告对标题的使用造成了公众混淆时，标题才可受到不正当竞争法的保护。     

Modified Shotguns in Turkey from 2006 to 2008

Abstract:  This study investigates the legal status of modified shotguns in Turkey by examining the cases submitted to the Aydın Regional Criminal Laboratory between January 2006 and August 2008. A total of 351 shotguns used in crimes were examined. These guns were evaluated in respect of their type, size, caliber, fitness for use, and legal classification. Eleven percent of these shotguns had been modified and it was found that 55% of the modified shotguns were classified according to law 6136 and qualified as a pistol and 45% were classified according to law 2521 and qualified as nonstandard shotguns. Within the Turkish criminal justice system, a nonstandard shotgun attracts a less stringent sentence than a pistol. It would therefore appear that this sentencing structure is considered when modifying shotguns in Turkey. This is clearly a loop-hole in the legislation that could perhaps be investigated and closed.     

Characteristics of Backspatter on the Firearm and Shooting Hand—An Experimental Analysis of Close‐range Gunshots

Contact and close‐range gunshot injuries can produce bloodstains on the shooting hand and weapon. In this study, backspatter was analyzed in experimental horizontal pistol shots into blood‐filled sponges. The shooting distances were set between 0 and 45 cm. With increasing shooting distance, there was a significant decrease in the degree of backspatter. Microspatter could be detected on the weapon and shooting hand up to a shooting distance of 40 cm. They were predominantly located on thumb and index finger as well as the radial dorsal aspects of the hand. Fine spray of microspatter combined with elongated droplets in the shape of exclamation marks was found at contact and 2‐cm distance shots. An angular calculation based on the shape of the bloodstains was possible up to a shooting distance of 2 cm. No bloodstains were detected beyond 45 cm.     

Suicide by air rifle and shotgun

We report the case of a 39-year old white male who committed suicide by shooting himself with an air rifle and a shotgun. The ballistics of air guns and rifles, with particular reference to the Sheridan air rifle, are reviewed. Only two cases of multiple firearm suicide have been reported; both involved simultaneously fired handguns. Ours is the first case, to our knowledge, of an air rifle and a shotgun used in sequence to commit suicide.     

The influence of a possible contamination of the victim's clothing by gunpowder residue on the estimation of shooting distance

A study was conducted to assess the influence of a possible contamination of the victim's clothing by gunpowder residue on the estimation of shooting distance. The study was focused on the scenario in which the contamination might be caused by the surface on which the shot victim could fall. Contamination of two types of textile was examined after contact with two types of surfaces. One round was fired above those surfaces (the line of firing parallel to the surface) prior to the contact. It was found that few gunpowder residue particles could be transferred to the clothing. These findings should be taken into account when interpreting results for shooting distance estimation in cases when a minute quantity of gunpowder residue particles is found around the bullet entrance hole.     

Accidental firearm fatalities during hunting

Swedish legislation concerning firearms is highly restrictive. It is illegal to possess weapons (except airguns) without a license. From 1970 through 1982, there were 79 accidental firearm fatalities in Sweden. This number, corresponding to 0.074/100,000/year, is very low in comparison with similar statistics worldwide. Of these fatalities, 47 were associated with hunting and were studied carefully. Despite an increase in both the popularity of hunting and in licensing of weapons, on change in the number of accidents per year could be confirmed. Twenty-nine accidents occurred during small game hunting, of which 24 involved shotguns, and 18 occurred during moose hunting. The mean age overall was 46 years. All victims and shooters were men. Most accidents occurred before noon and during the autumn. During moose hunting, the victim most commonly was either mistaken for game or was standing beyond game. During small game hunting, the most common reason for death was improper handling of the weapon. Firing of defective weapons caused at least 10 fatal accidents. Alcohol inebriation was uncommon. It is unlikely that more restrictive firearm legislation would further decrease the number of fatal accidents. Instead, we believe that accidental firearm fatalities during hunting can be prevented by safer and more careful handling of weapons, including unloading weapons before transporting them; by replacing older weapons with more modern and safer ones; and by not allowing children to handle weapons. No shots should be fired until it is clarified that the target really is a game animal, and when hunting with rifles, the fields of fire should be clarified beforehand. Shooters at stand must be instructed not to leave their stands until explicitly told to do so.     

Time periods of GSR particles deposition after discharge-final results

The elemental objects of the research study are: determination of time periods corresponding to gunshot residue particles (GSR) deposition after the shot from selected pistols and a revolver, and evaluation of the deposited particles number. For several shooting experiments were used a pistol CZ model 85, caliber 9 mm Luger with common ammunition 9 mm Luger FMJ Sellier & Bellot, a pistol CZ model 70, caliber 7.65 mm Browning (32 ACP) with common 7.65 mm Browning FMJ Sellier & Bellot ammunition and a revolver S&W Modell 60, barell length 2-1/8', cal. .38 Special with common Sellier&Bellot (FMJ) ammunition. The results of the study have indicated the behavior of GSR particles deposited after a single discharge. The overall time interval of GSR particles deposition and the number of deposited particles with the above mentioned arms and ammunition were established. The results can potentially be used for clarifying the situation at crime scenes and for subsequent interpretation of GSR evidential value in caseworks.     

A novel method for the analysis of discharged smokeless powder residues

A novel method for the estimation of intermediate-long firing distance range is proposed. The method is based on the characterization and chemical analysis of the smokeless powder particles on the target. An adhesive lifter is applied to collect the suspected gunshot residues (GSRs) from the surface of an object, and a Modified Griess Test (MGT) is carried out after alkaline hydrolysis on the adhesive lifter. Visualized particles are removed from the adhesive lifter under a microscope. Two systems are used for the analysis of organic discharge residues from the smokeless powder: (1) gas chromatography/thermal energy analysis (GC/TEA) for the analysis of nitroglycerine (NG) and 2,4-dinitrotoluene (2,4-DNT), (2) gas chromatography/mass spectrometry (GC/MS) for the identification of organic components such as DNT, NG, and some stabilizers. By using this procedure and confirming that the suspected particles are indeed GSR, one can estimate the intermediate-long firing distance of c. 0.75-3 m in the presence of very few particles and provide information for the classification of ammunition type in casework.     

Preliminary evaluation of the persistence of organic gunshot residue

The organic components of gunshot residue (OGSR, also called firearms discharge residue (FDR) or cartridge discharge residue (CDR)) have been studied and discussed in the literature. These residues, consisting of particulates such as burned and unburned powder as well as molecular compounds, are rarely used in casework except for purposes such as shooting reconstructions. Molecular compounds that survive the firing event or that are created as a result of the firing event could, with focused research and development, open a new avenue for forensic gunshot residue analysis. In this study, the persistence of organic gunshot residue was evaluated using diphenylamine (DPA) as a target analyte and ion mobility spectrometry (IMS) as the detection system. Samples were collected from hands using a solvent swabbing technique and the swab was analyzed using direct thermal desorption for sample introduction into the IMS. OGSR was found to persist for at least 4h. Although DPA is a widely used industrial compound, analysis of numerous blank and background samples (n～100) did not show any significant response for DPA using this detector. Variations were noted among individuals and as such, the data set does not support estimation of a half-life as has been done for traditional primer residues. No secondary transfers were observed, suggesting the possibility of skin adhesion via interactions between the lipophilic organic compounds and skin lipids. IMS proved valuable as a means of generating patterns for forensic pattern matching and shows promise as a screening tool applied to firearms discharge.     

Desorption electrospray tandem MS (DESI-MSMS) analysis of methyl centralite and ethyl centralite as gunshot residues on skin and other surfaces

Abstract:  A direct and sensitive method for the detection of methyl centralite (MC) and ethyl centralite (EC) as gunshot residues (GSRs) has been developed. This method uses desorption electrospray ionization (DESI)-tandem mass spectrometry and directly desorbs and detects analytes from surfaces without any sampling process. Typical transitions for MC and EC, m/z 241 to m/z 134 and m/z 269 to m/z 148, respectively, were used to improve the assay sensitivity. It has been shown that MC and EC can be detected on various surfaces, with detection limits of 5–70 pg/cm². Interferences, detection time after shooting and the number of times hands were washed after shooting were also evaluated. None of the materials interfered with the results and the detection window for organic GSRs was up to 12 h and hands could be washed at least six times. Further samples were analyzed to confirm the reliability of this method, and showed that it could discriminate shooters from nonshooters. This method should be of significance in forensic science, especially in analyzing GSRs, because of its simplicity, high throughput, and the direct detection of MC and EC on suspects' hands, clothes, and hair.