A simple method for collection of gunshot residues from clothing.

Simple equipment for the sampling of gunshot residue particles from clothing, inside of bags, pockets, etc, is described. Collection was achieved by vacuuming through a double filtration system constructed from a Nucleopore aerosol holder connected to an ordinary vacuum cleaner. The collected particles were examined by scanning electron microscopy. Good results were observed in functional tests of this equipment and the method has been introduced into casework in our laboratory. Various experiments on possible contamination of clothing by GSR particles were performed. The usefulness of clothing as evidence material in searching for GSR particles is discussed.     

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.     

Image analysis as an adjunct to sodium rhodizonate test in the evaluation of gunshot residues: an experimental study

It is important to investigate the clothing, as well as the body, to determine the range of fire of entry wounds in firearm injuries. Clothing can affect the amount of gunshot residues (GSR) reaching the body and their distribution. The amount and distribution of the GSR also vary according to the distance between the firearm and the target. Sodium rhodizonate test provides valuable data when clothing is available for examination. In the absence of clothing, light microscopic examinations may add additional information regarding the range of fire. In this study, a sodium rhodizonate test was done on 80 garment samples containing the bullet entrance. The 80 calfskin samples were processed histologically and were stained using Alizarin Red S. These were also evaluated with computer-assisted image analysis. Gross residues were seen on military camouflage clothing in samples from < or = 45-cm group. White flannel undershirts under the military camouflage contained rhodizonate-positive particles only around the contact wounds. With image analysis, however, the residues could be detected also in the skin samples of the 2.5-cm- and 5-cm-range groups. We suggest that the image analysis can be combined with other techniques and it can provide valuable data in the determination of entry wounds and also in the estimation of firing distance.     

The random presence of glass and paint on the clothing and footwear of members of the general population: A US baseline survey at various seasons

This study assists the interpretation of glass and paint evidence by filling an existing gap in the background occurrence that reflects the socioeconomic and demographic circumstances in the United States. The collection was performed in a college US city (Morgantown, West Virginia) to determine the effect of the type of clothing worn at different seasons on the presence of glass and paint. Tape lifts and sole scrapings (1038) were collected from 210 participants and up to six clothing and footwear areas per individual. Glass fragments were analyzed via polarized light microscopy (PLM), refractive index (RI), micro-X-Ray fluorescence (μXRF), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), while paint specimens were examined by light microscopy and infrared spectroscopy (μFTIR). Higher occurrences of glass and paint were found in the winter season. The winter collection yielded 10 glass fragments and 68 paint particles, whereas the summer collection resulted in one glass fragment and 23 paint particles. The percentage of individuals with traces varied between seasons; 7% of individuals in the winter and 0.9% in the summer had glass, whereas 36% of individuals in the winter and 19% in the summer bore paint. Lastly, when considering the overall garment and footwear areas, glass was detected in 1.4% of the winter set, compared to 0.2% in the summer collection; paint was found in 9.2% of the winter collection, whereas only 4.2% was found in the summer set. There were no instances where both glass and paint were detected on the clothing and footwear of the same individual.     

A simple method for detection of gunshot residue particles from hands, hair, face, and clothing using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX).

We devised a simple and rapid method for detection of gunshot residue (GSR) particles, using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX) analysis. Experiments were done on samples containing GSR particles obtained from hands, hair, face, and clothing, using double-sided adhesive coated aluminum stubs (tape-lift method). SEM/WDX analyses for GSR were carried out in three steps: the first step was map analysis for barium (Ba) to search for GSR particles from lead styphnate primed ammunition, or tin (Sn) to search for GSR particles from mercury fulminate primed ammunition. The second step was determination of the location of GSR particles by X-ray imaging of Ba or Sn at a magnification of x 1000-2000 in the SEM, using data of map analysis, and the third step was identification of GSR particles, using WDX spectrometers. Analysis of samples from each primer of a stub took about 3 h. Practical applications were shown for utility of this method.     

An investigation into the presence of petrol on the clothing and shoes of members of the public

First, the clothing and shoes from 29 participants who had recently filled their vehicles with petrol were analysed for any traces of petrol. No traces of petrol were found on any of these items. Secondly, the clothing and shoes from 17 participants who had recently used a petrol-powered lawn mower were also analysed for petrol. Petrol was detected on two pairs of shoes from different participants. Components of petrol were detected on a set of clothing from a third participant, however, there were insufficient components present in this sample to confirm the presence of petrol. No traces of petrol were found on the items from the remaining 14 participants. Thirdly, the clothing from a forecourt attendant, a mechanic and a professional lawn mower were analysed at the end of a number of shifts. Petrol was detected on the upper and lower clothing from the forecourt attendant at the end of one shift. No petrol residues were found on the forecourt attendant after a second shift, or on the mechanic's clothing after two separate shifts or on the professional lawn mower's clothing after three separate shifts. These results can be used to assist the forensic analyst in assessing the chance of finding traces of petrol on clothing and shoes after the wearer has performed common activities that involve petrol.     

Recovery of Spray Paint Traces from Clothing by Beating

Manual recovery of spray paints from textiles using a microscope, the routine method in many laboratories, is often laborious. Beating the clothing with a plastic rod, the routine method used for recovery of glass traces within the authors’ laboratory, is proposed as an alternative. The efficiency of the method was evaluated by spray tests with fluorescent paint. In these tests, paint particles in the acquired debris samples, as well as those remaining on the textiles, were investigated. The results show that beating is an efficient way to recover and concentrate paint particles. A good efficiency for jeans fabric and rough knitwear is reported. The results appeared to be less satisfactory for smooth woven fabric. Application of the method in casework was effective for graffiti paints as well as for flaked car paint.     

Statistical Challenges in the Quantification of Gunshot Residue Evidence

The discharging of a gun results in the formation of extremely small particles known as gunshot residues (GSR). These may be deposited on the skin and clothing of the shooter, on other persons present, and on nearby items or surfaces. Several factors and their complex interactions affect the number of detectable GSR particles, which can deeply influence the conclusions drawn from likelihood ratios or posterior probabilities for prosecution hypotheses of interest. We present Bayesian network models for casework examples and demonstrate that probabilistic quantification of GSR evidence can be very sensitive to the assumptions concerning the model structure, prior probabilities, and the likelihood components. This finding has considerable implications for the use of statistical quantification of GSR evidence in the legal process.     

Glass on clothing and shoes of members of the general population and people suspected of breaking crimes.

The outer clothing and footwear of 122 people attending a university gymnasium and a private gymnasium were searched for fragments of glass. Both the surfaces and the pockets of the clothing and the uppers and soles of the footwear were searched. New Zealand forensic glass cases have been reviewed to determine the amount of non-matching glass present on the clothing of people who are suspected of breaking crimes. Data from 114 suspects who had no matching glass on their clothing and shoes were accumulated. Statistical modelling techniques have been applied to the data collected.     

Use of fecal material to associate a suspect with a crime scene: report of two cases

Fecal matter analyses were applied to two cases: a homicide and a robbery. Scrapings of fecal matter removed from samples of clothing obtained from a homicide suspect were examined for their plant cell and cell fragment content and compared with fecal matter from a rape-homicide victim and scrapings from her clothing. Scrapings were hydrated and examined microscopically. Types of food plants were identified from the observed cells by comparison with known food plants. A similar analysis was conducted on the clothing of a robbery suspect and compared with fecal material left at the crime scene. The results showed that, respectively in the two cases, the reference samples were remarkably similar, if not identical, to those from the suspects' clothing.     

The showup identification procedure: An exploration of systematic biases

Purpose. Showups are common, yet little research has investigated the biasing factors that may influence showup identifications. We investigated the effects of cross‐race conditions and clothing bias on showup identification decisions. Additionally, we explored identification decisions made in a subsequent lineup dependent on race, clothing, and showup‐target‐presence. Methods. Participants watched a mock crime and were presented with a showup in which suspect race, target‐presence, and the clothing worn by the suspect were varied. Following a delay, participants viewed a target‐present or ‐absent lineup and were asked to make a second identification decision. Results. Presentation of the suspect in the clothing worn by the perpetrator increased choosing rates in both own‐race and other‐race conditions. Despite this, differential patterns of decision response latencies indicated that eyewitnesses may use clothing information differently when making own‐race compared to other‐race identification decisions. No evidence for an own‐race bias in showup identifications was found; however, other‐race lineup identifications were less accurate than own‐race lineup identifications. Further, participants in own‐race and other‐race conditions differed in the extent to which they were affected by multiple identification procedures. Viewing an own‐race innocent suspect in a showup increased subsequent false lineup identifications, while choosing the innocent suspect from the showup was necessary to increase false lineup identifications in other‐race conditions. Conclusions. Different situational factors may affect the identification accuracy of eyewitnesses in own‐race and other‐race conditions for both showup and lineup procedures. Particular caution is advised when showups are clothing‐biased and multiple identification procedures are used.     

Study of the adhesion of explosive residues to the finger and transfer to clothing and luggage

It is important to understand the extent of transfer of explosive particles to different surfaces in order to better evaluate potential cross-contamination by explosives in crowded security controls such as those at airports. This work investigated the transfer of nine explosive residues (ANFO, dynamite, black powder, TNT, HMTD, PETN, NH₄NO₃, KNO₃, NaClO₃) through fingerprints from one surface to another. First, the extent of adhesion of explosive residues from different surfaces to the bare finger, nitrile and latex gloves was studied. Then, the transfer of explosive residues from one surface to another through fingerprints was investigated. Cotton fabric (hereinafter referred to as cotton) as clothing material and polycarbonate plastic (hereinafter referred to as polycarbonate) as luggage material were chosen for the experiments. These surfaces containing explosive particles were imaged using a reflex camera before and after the particles were transferred. Afterwards the images were processed in MATLAB where pixels corresponding to explosive residues were quantified. Results demonstrated that transfer of explosive residues frequently occurred with certain differences among materials. Generally, the amount of explosive particles adhered to the finger decreased in the following order: skin>latex>nitrile, while the transfer of particles from the finger to another surface was the opposite. The adhesion of explosive residues from polycarbonate to the finger was found to be better compared to cotton, while the amount of particles transferred to cotton was higher.     

Shooting Through Clothing in Firearm Suicides

Abstract: There is a longstanding empirical rule that people who commit suicide rarely shoot through their clothing, but rather put it aside to expose the nude skin. Signs of shots through clothing have always been considered suspicious, raising presumptions of the presence of an abettor. Our report, based on a retrospective study of fatal suicidal firearm injuries from the years 1980 to 2007, points out that suicide victims only rarely remove clothing from the site of the future entry wound. The report covered 43 cases with fatal gunshot wounds in the area of the thorax, with only four persons (9%) removing the clothing present in the area of the subsequent self‐inflicted wound. Defects present on the clothing of a victim cannot, therefore, be understood as an absolute criterion for disproving the possibility of suicide, and nor do they necessarily indicate an unfortunate accident or homicide. If, however, the suicide victim removes the clothing from the area of the future wound, then this is almost always an indication of suicide.     

The transfer of petrol on to clothing and shoes while pouring petrol around a room

This study was aimed at measuring the approximate amount of petrol transferred on to the clothing and shoes of a person during the action of pouring petrol around a room. Two different heights of pouring and two different types of floor surface (carpet and concrete) were investigated. Results show that for all the combinations examined petrol was always transferred to the shoes and often transferred to the upper and lower clothing. This information illustrates the necessity of analysing the clothing and particularly the shoes of any suspected arsonists for the presence of hydrocarbon fuels.     

Freshwater diatom transfer to clothing: Spatial and temporal influences on trace evidence in forensic reconstructions

Environmental indicators are increasingly sought and analysed in a range of forensic reconstructions. Although the majority of casework and research studies are concerned with the criminal investigation of terrestrial habitats (soils, sediments, plants etc.), freshwater environments are also frequently encountered as crime scenes. As such, microalgae, particularly diatoms, may provide useful circumstantial trace evidence following their transfer to a victim or perpetrator. Diatom analysis is a relatively underused technique in forensic ecology, although an increased empirical research focus is beginning to recognise the evidential value of a transferred assemblage. This study aimed to examine three of the spatial and temporal variables known to influence the extent of an initial transfer of trace particulates, within the context of freshwater diatoms to clothing. A series of experiments were designed to consider the impact of recipient surface characteristics (clothing type), source environment conditions (seasonality), and morphological (type of diatom) variability, on the total number (no. per cm²) and species richness (total no. sp.) of an evidential diatom sample recovered from clothing. Nine commonly used clothing materials were immersed in a freshwater river at three times of year – the early and late spring and in the winter. Diatoms were recovered using a H₂O₂ extraction technique and examined microscopically. The results demonstrated that diatom transfer to clothing varies significantly, with a greater abundance and a higher species richness transferred to coarse woven surfaces including acrylic, linen, and viscose. Significantly fewer diatoms were transferred to clothing in the winter, in line with seasonal fluctuations in the source environment diatom community. Furthermore, variation in the relative abundance of particular diatom species was identified between clothing types, provisionally suggesting that morphological characteristics may also support or limit the transfer of material. These findings highlight that, although clothing may offer a valuable repository of freshwater diatom trace evidence, the interpretation of evidential material should be approached within an exclusionary framework. Thus, empirical data has been generated to develop evidence bases within forensic ecology, demonstrating some of the spatial and temporal factors which may contribute to or limit the transfer of evidence.     

Toner Particles as Forensic Evidence: Microanalytical Characterization of Known Toner and Recognition of Toner in Environmental Samples*†‡

Modern printing toners represent a prime example of subvisible particles that can be easily transferred to hands, clothing, and other surfaces. To explore the potential evidentiary value of toner particles, toner samples were collected from known printer cartridges and characterized by various microanalytical techniques to establish the properties most useful for recognition, identification, and comparison. Environmental samples (i.e., dust) were then collected from various locations at varying distances from toner-based printers, using both tape lifts and carbon adhesive stubs, to assess the possibility of detecting toner. By light microscopy, toner can be recognized on the basis of particle size and shape, as well as color. Further examination of the micromorphology in the field emission scanning electron microscope reveals characteristic morphologies and differences in surface texture and shape among toner sources. Raman spectroscopy provides chemical identification of the pigment (or pigment class) and, in some cases, also permits identification of the polymer component. While black and blue pigment chemistry remained constant among toner varieties that were studied (copper phthalocyanine and carbon black), variation in yellow and magenta pigments was observed. Analysis of dust samples collected from various environments demonstrated that while toner is consistently detectable in close proximity to printers (within 2 feet), it also can be detected in dust collected in nearby rooms. This research demonstrates that toner particles can be located, characterized, and discriminated, using a suite of microanalytical methods that are applicable to forensic casework.     

Lineup Identification by Children: Effects of Clothing Bias

This study examined effects of clothing cues on children's identification accuracy from lineups. Four- to 14-year-olds (n = 228) saw 12 video clips of individuals, each wearing a distinctly colored shirt. After watching each clip children were presented with a target-present or target-absent photo lineup. Three clothing conditions were included. In 2 conditions all lineup members wore the same colored shirt; in the third, biased condition, the shirt color of only one individual matched that seen in the preceding clip (the target in target-present trials and the replacement in target-absent trials). Correct identifications of the target in target-present trials were most frequent in the biased condition, whereas in target-absent trials the biased condition led to more false identifications of the target replacement. Older children were more accurate than younger children, both in choosing the target from target-present lineups and rejecting target-absent lineups. These findings suggest that a simple clothing cue such as shirt color can have a significant impact on children's lineup identification accuracy.     

Effect of water immersion on seminal stains on cotton cloth

Reports on identification of seminal stains and spermatozoa on washed clothing are available. However, their detection on such clothing seems to depend on the washing material and the procedure adopted. It is reported here that prolonged immersion in water does not affect the detection of stains and spermatozoa.Results of experiments on water-immersed cotton clothing from 12 to 144 hours of water immersion are presented here. It is seen that intact human spermatozoa could be detected on such material even at 120 hours.     

A method for enhancing gunshot residue patterns on dark and multicolored fabrics compared with the modified Griess test

In using infrared or infrared-enhanced photography to examine gunshot residue (GSR) on dark-colored clothing, the GSR particles are microscopically examined directly on the fabric followed by the modified Griess test (MGT) for nitrites. In conducting the MGT, the GSR is transferred to treated photographic paper for visualization. A positive reaction yields an orange color on specially treated photographic paper. The examiner also evaluates the size of the powder pattern based on the distribution of nitrite reaction sites or density. A false-positive reaction can occur using the MGT due to contaminants or dyes that produce an orange cloud reaction as well. A method for enhancing visualization of the pattern produced by burned and partially unburned powder is by treatment of the fabric with a solution of sodium hypochlorite. In order to evaluate the results of sodium hypochlorite treatment for GSR visualization, the MGT was used as a reference pattern. Enhancing GSR patterns on dark or multicolored clothing was performed by treating the fabric with an application of 5.25% solution of sodium hypochlorite. Bleaching the dyes in the fabric enhances visualization of the GSR pattern by eliminating the background color. Some dyes are not affected by sodium hypochlorite; therefore, bleaching may not enhance the GSR patterns in some fabrics. Sodium hypochlorite provides the investigator with a method for enhancing GSR patterns directly on the fabric. However, this study is not intended to act as a substitute for the MGT or Sodium Rhodizonate test.