Gunshot residue and brakepads: Compositional and morphological considerations for forensic casework

Tucker, William A.; Lucas, Nick; Seyfang, Kelsey E.; Kirkbride, K. Paul; Popelka-Filcoff, Rachel S.

doi:10.1016/j.forsciint.2016.11.024

Cited by 24 publications

(11 citation statements)

References 11 publications

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“…Literature studies [12][13][14][15][16][17] confirm that the dimensional structure of the GSR particles consists of spherical particles as a result of a random distribution. Vermeij et al [10] showed that differences may exist in the dimensional structures of the GSR particles outside of the spherical structures.…”

Section: Introductionmentioning

confidence: 98%

The relationship between gunshot-residue particle size and Boltzmann distribution

Kara

2020

Forensic Sciences Research

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Gunshot-residue (GSR) particles usually form spherical structures, have special dimensions, and a composition that consists of burned and partially unburned matter with a 0.5-50-mm diameter (sometimes larger). The GSR particle-size distributions have been argued to be caused by the effects of equilibrium-surface distributions during formation and have not yet been correlated with a theoretical analysis or probability distribution. This study proposes a model to explain the GSR particle-size distribution quantitatively. Based on the data, and, as predicted by our model, the number of GSR particles decreases proportionally to the inverse square of the GSR particle size as the particle size increases. This result occurs because of the abundance of microstructures that are encountered in the GSR particles.

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Section: Introductionmentioning

confidence: 98%

The relationship between gunshot-residue particle size and Boltzmann distribution

Kara

2020

Forensic Sciences Research

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“…The literature presents several studies that detect or quantify GSR, either in body parts or clothing, which can be used to aid criminal expertize to elucidate crimes (27)(28)(29). Research also points to the use of larvae in the determination of Pb, Ba, and Sb, from GSR, in tissue samples and corpse surfaces associated with sensitive analytical techniques, showing the potential of the use of larvae for the observation/detection of Pb, Ba, and Sb (8,18,19,30).…”

Section: Resultsmentioning

confidence: 99%

Detection of Pb, Ba, and Sb in Cadaveric Maggots and Pupae by ICP‐MS*

Costa¹,

Santos

Corrêa

et al. 2020

Journal of Forensic Sciences

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The concentrations of lead (Pb), barium (Ba), and antimony (Sb), characteristic of GSR, were determined in soil sediments and immature (larvae) of cadaveric flies of the family Calliphoridae, by inductively coupled plasma mass spectrometry (ICP-MS). This research refers to a case study from two real crime scenes in which the corpses were in an advanced state of decomposition. In case 1, the victim had holes similar to gunshot wounds, and in case 2, there was no evidence of perforations in the corpse. Soil sediment collection was performed at three different points of the terrain, at a minimum distance of 10 m from the corpse, for cases 1 and 2. In relation to the collection of immatures, larvae were collected in regions of the mouth, nose, and orifices similar to the entry of firearms projectile into the body, for case 1, and collection of larvae and pupae, located on the body and underneath it, for case 2. It was possible to detect and quantify the three elements of interest (Pb, Ba, and Sb) by ICP-MS in both sediment and cadaveric larvae. Concentrations of 4.44, 8.74, and 0.08 μg/g were obtained for Pb, Ba, and Sb, respectively, in the soil for case 1. For the case 2, the concentrations in Pb, Ba, and Sb were from 16.34 to 26.02 μg/g; from 32.64 to 57.97 μg/g and from 0.042 to 0.30 μg/g, respectively. In the larvae, Pb, Ba, and Sb were quantified in cases 1 and 2 with a concentration of 6.28 and 1.78 μg/g for Pb, 1.49 and 2.94 μg/g for Ba, 0.50 μg/g and

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“…For instance, one occupation with a high source of contamination is an automotive mechanic. The brake pads on a car often contain barium sulfate and antimony trisulfide to help with heat stability and lubrication of the brake pads to reduce friction 39 . Due to this, the chemical makeup of brake pads has the possibility of being mistaken for…”

Section: Current Challenges and Advances On Gsr Detectionmentioning

confidence: 99%

“…These samples also tested positive for elemental compositions that were consistent with GSR. However, it was determined that when XRF is combined with SEM-EDS analysis, low false positive rates occurred due to the morphological differences between a typical GSR particle and typical brake pad particle 39 .…”

Section: Gsrmentioning

confidence: 99%

Chemical Analysis of Firearm Discharge Residues Using Laser Induced Breakdown Spectroscopy

Pyl¹,

Helen²

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According to the Gun Violence Archive, in 2017, firearms were involved in 57,134 criminal incidents in the United States. The detection of firearm discharge residues (FDR), including inorganic and organic gunshot residues, can provide essential information in such investigations. For instance, when the question of suicide or murder arises, estimating the barrel to victim distance plays a critical role in the outcome of the case. In addition, clothing, wounds and other target materials are often inspected to determine if a bullet has produced an entry or exit orifice. Currently, the most common method for distance determination and identification of bullet entrance holes is by chemical colorimetric tests that react in the presence of nitrites or lead. Although these color tests are widely used in forensic laboratories, the major pitfall is their variability and poor selectivity for gunshot residues. Dark or bloody items significantly diminish the efficacy of these assays, they are difficult to perform on non-movable or large objects, and false positives can be derived from oil, dirt, and other common contaminants. The chance of outside sources affecting the color distribution pattern has led to the exploration of alternative instrumental methods for estimating a shooting distance, including Atomic Absorption Spectroscopy (AAS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray fluorescence (XRF), and Atomic Force Microscopy (AFM). Nevertheless, these instrumental methods have limitations for GSR analysis, as well, such as destruction of the sample, long time of analysis, or complex sample preparation. Therefore, there is a critical need for the development of an analytical method that is sensitive to GSR, fast, practical, non-invasive, objective, and accurate. The primary goal of this study was to investigate the capabilities of LIBS for shooting distance determination and identification of FDR on substrates of interest. The central hypothesis of this research was that Laser-Induced Breakdown Spectroscopy would improve the scientific reliability of the detection and observation of gunshot residues. This assumption was based on the ability of LIBS to perform simultaneous multi-elemental detection at low ppm levels, LIBS' superior selectivity, and the potential for confirmation of numerous emission species per analyte. To assess the forensic utility of LIBS, the method was developed and validated for the analysis of substrates commonly found during firearm-related crimes. Residues from different ammunitions and firearms were analyzed off 133 fabrics, glass, drywall, and wooden samples. Statistical methods, like principal component analysis and multivariate discriminant analysis were performed to estimate shooting distances and identify the presence of GSR residues. Color tests lead to misclassification of 9 out of 35 unknown shooting distances (26%), while the LIBS method correctly classified 100% of the unknown distance testing samples by Discriminant Analysis. Additionally, LIBS was able to correctly identify ...

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Gunshot residue and brakepads: Compositional and morphological considerations for forensic casework

Cited by 24 publications

References 11 publications

The relationship between gunshot-residue particle size and Boltzmann distribution

The relationship between gunshot-residue particle size and Boltzmann distribution

Detection of Pb, Ba, and Sb in Cadaveric Maggots and Pupae by ICP‐MS*

Chemical Analysis of Firearm Discharge Residues Using Laser Induced Breakdown Spectroscopy

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