Mountain Road, VA, United States
Mountain Road, VA, United States

Time filter

Source Type

Stoney D.A.,Stoney Forensic Inc. | Neumann C.,Two Ns Forensics Inc. | Neumann C.,South Dakota State University | Mooney K.E.,Defense Forensic Science Center | And 2 more authors.
Forensic Science International | Year: 2015

Environmentally acquired very small particles (VSP), present on the surfaces of carpet fibers, have shown potential for the association of fibers with their carpet source. To unlock this potential, research is required addressing a number of areas, including the application of methods under realistic casework conditions and the utilization of computational methods for the refinement and testing of the approach.In this work field collections of carpet fibers were conducted by crime scene practitioners under realistic casework conditions. VSP were isolated using previously developed methods, and analyses were conducted using SEM/EDS analytical protocols in an operational crime laboratory setting. Computational methods were designed, allowing sets of hundreds to thousands of VSP to be characterized. Classifiers were designed to associate and discriminate among specimens. These classifiers were applied to the VSP data for specimens collected by crime scene practitioners, as well as to a previously collected research dataset. Quantitative measures of correspondence and probative value were designed based on the classification measures and successfully applied to both sets of VSP data.Particle sets larger than 500 showed strong promise for quantitative associations with their sources. The use of larger numbers of target particle types (TPTs) showed strong promise to improve the performance of classification and association.Overall, the usefulness of VSP to provide objective, quantitative associations has been established. Because VSP are acquired post-manufacture, these methods can address fundamental limitations to probative value that arise when class characteristics, determined by manufacture, are shared among mass produced commodities.These findings are of broad significance for the future of trace evidence analysis. The results of this research are likely extendable, with minor modifications, to other trace evidence types (such as glass, tape and human hair), and are expected to contribute significantly for those types of trace evidence that have long been considered of low evidential value (such as undyed cotton and animal hairs). Furthermore, entirely new approaches to trace evidence are enabled by exploiting VSP profiles, such as comparing different types of trace evidence with one another and comparing VSP defined by crime scene or suspect environments to those on virtually any item of physical evidence. © 2015 Elsevier Ireland Ltd.


Stoney D.A.,Stoney Forensic Inc. | Stoney P.L.,Stoney Forensic Inc.
Forensic Science International | Year: 2015

An effective trace evidence capability is defined as one that exploits all useful particle types, chooses appropriate technologies to do so, and directly integrates the findings with case-specific problems. Limitations of current approaches inhibit the attainment of an effective capability and it has been strongly argued that a new approach to trace evidence analysis is essential.A hypothetical case example is presented to illustrate and analyze how forensic particle analysis can be used as a powerful practical tool in forensic investigations. The specifics in this example, including the casework investigation, laboratory analyses, and close professional interactions, provide focal points for subsequent analysis of how this outcome can be achieved. This leads to the specification of five key elements that are deemed necessary and sufficient for effective forensic particle analysis: (1) a dynamic forensic analytical approach, (2) concise and efficient protocols addressing particle combinations, (3) multidisciplinary capabilities of analysis and interpretation, (4) readily accessible external specialist resources, and (5) information integration and communication.A coordinating role, absent in current approaches to trace evidence analysis, is essential to achieving these elements. However, the level of expertise required for the coordinating role is readily attainable. Some additional laboratory protocols are also essential. However, none of these has greater staffing requirements than those routinely met by existing forensic trace evidence practitioners. The major challenges that remain are organizational acceptance, planning and implementation. © 2015 Elsevier Ireland Ltd.


Stoney D.A.,Stoney Forensic Inc. | Stoney P.L.,Stoney Forensic Inc.
Forensic Science International | Year: 2015

The historical development, contributions and limitations of the two traditional approaches to trace evidence analysis are reviewed. The first approach was as generalist practitioner, looking broadly at an assemblage of many different particle types. The second was that of specialist practitioner, with attention focused on one specific particle type. Four factors have significantly impacted the effectiveness of these approaches: (1) increasing technological capabilities, (2) increasing complexity in the character of manufactured materials, (3) changes in forensic laboratory management, and (4) changing scientific and legal expectations. The effectiveness of each approach is assessed within the context of these changes.More recently, new technologies have been applied to some trace evidence problems, intended to address one or more limitations. This has led to a third approach founded on discrete, highly technical methods addressing specific analytical problems. After evaluating the contributions and limitations of this third approach, we consider the different ways that technologies could be developed to address unmet needs in forensic trace evidence analysis. The route toward effective use of new technologies is contrasted with how forensic science laboratories are currently choosing and employing them. The conclusion is that although new technologies are contributing, we are not on a path that will result in their most effective and appropriate use. A new approach is required.Based on an analysis of the contributions of each of the three exisiting approaches, seven characteristics of an effective trace evidence analysis capability were determined: (1) particle traces should be a major problem-solving tool, (2) there should be readily available, straightforward methods to enable their use, (3) all available and potentially useful particle types should be considered, (4) decisions to use them should be made in the context of each case, guided by what they can contribute to the case and how efficiently they can do so, (5) analyses should be conducted using appropriate technologies, (6) findings should be timely and directly integrated with case-specific problems, and (7) new technologies should be used to improve the overall effectiveness of the capability.Clearly new technologies have the potential to revolutionize forensic trace evidence, but just as clearly some of the traditional capabilities have been rendered ineffective, or lost entirely, by the way we have come to approach the problem. Having critically defined the current limitations of and the desired outcomes, the next focus should be consideration of alternative approaches that might achieve such a result. © 2015 Elsevier Ireland Ltd.


Twenty-four herbal dietary supplement powder and extract reference standards provided by the National Institute of Standards and Technology (NIST) were investigated using three different commercially available DNA extraction kits to evaluate DNA availability for downstream nucleotide-based applications. The material included samples of Camellia, Citrus, Ephedra, Ginkgo, Hypericum, Serenoa, and Vaccinium. Protocols from Qiagen, MoBio, and Phytopure were used to isolate and purify DNA from the NIST standards. The resulting DNA concentration was quantified using SYBR Green fluorometry. Each of the 24 samples yielded DNA, though the concentration of DNA from each approach was notably different. The Phytopure method consistently yielded more DNA. The average yield ratio was 22:3:1 (ng/L; Phytopure:Qiagen:MoBio). Amplification of the internal transcribed spacer II region using PCR was ultimately successful in 22 of the 24 samples. Direct sequencing chromatograms of the amplified material suggested that most of the samples were comprised of mixtures. However, the sequencing chromatograms of 12 of the 24 samples were sufficient to confirm the identity of the target material. The successful extraction, amplification, and sequencing of DNA from these herbal dietary supplement extracts and powders supports a continued effort to explore nucleotide sequencebased tools for the authentication and identification of plants in dietary supplements. © Georg Thieme Verlag KG Stuttgart · New York.


Bowen A.M.,Stoney Forensic Inc. | Bowen A.M.,National Forensic Laboratory | Caven E.A.,Stoney Forensic Inc.
Geological Society Special Publication | Year: 2013

In recent decades, the polarizing light microscope has been slowly phased out of the geology curricula of many universities in the United States. This is unfortunate, as the polarizing light microscope is an instrument that is particularly well suited to overcoming problems typically encountered in forensic scenarios. Its versatility makes it uniquely powerful in provenance investigations in which sample size is limited and sample history is unknown. The polarizing light microscope can be used to determine the source rock type(s) of a sample of unconsolidated grains, either based on the mineral assemblage present in the sample or on properties observed for individual mineral grains or lithic fragments. Biological particles including pollen, spores, diatoms and botanical macerals can be identified and used to constrain the possible source of a sample. In addition, individual particles observed in the sample (geological, biological or anthropogenic) can be isolated and re-mounted for subsequent analyses that are useful for provenance determination. The inferences made can be used to produce maps illustrating potential source regions by means of geographical information systems (GIS). Several examples are provided to illustrate the various capabilities of the polarizing light microscope and its contributions to forensic soil analysis, specifically in forensic provenance investigations. © The Geological Society of London 2013.


Bowen A.,Stoney Forensic Inc. | Bowen A.,National Forensic Laboratory | Stoney D.,Stoney Forensic Inc.
Journal of Forensic Sciences | Year: 2013

Fibers are a commonly encountered evidence type and fiber comparisons are routinely conducted. When the characteristics of questioned and known fibers correspond, the probative value is limited because the characteristics compared are determined by their manufacture. It would be valuable to test the hypothesis that questioned fibers originated from a specific carpet. One means of testing this is to analyze fine particles on the fibers. A procedure was developed for removing adhering particles from fibers and preparing them for scanning electron microscopy/ energy dispersive X-ray spectrometry (SEM/EDS) analysis. The efficacy of several fluids (acetone, ethanol, hexanes, aqueous ethanol, aqueous sodium hexametaphosphate) and agitation methods (sonication and vortexing) for removing particles from fibers was evaluated. The most effective method evaluated was sonication in ethanol for 10 min. The recovered particles were filtered onto a polycarbonate filter and analyzed by automated SEM/EDS analysis to generate data on the particle assemblage. This method makes possible future research to test the within-item and between-item variability of particle assemblages on fibers. © 2013 American Academy of Forensic Sciences.


Stoney D.A.,Stoney Forensic Inc. | Bowen A.M.,Stoney Forensic Inc. | Stoney P.L.,Stoney Forensic Inc.
Forensic Science International | Year: 2015

Very small particles (VSP) are ubiquitous in our environment and are virtually ignored by forensic science. These particles range in size from an order of magnitude smaller than conventional trace evidence, down to the molecular level. Combinations of VSP provide an extraordinary, largely untapped resource for forensic associations and source attribution. This paper describes an initial effort to exploit VSP for one specific application.An approach was developed and tested for the SEM/EDS analysis of VSP recovered from the surfaces of carpet fibers - one of the most common types of trace evidence examined in crime laboratories. Our goal was to exploit existing computer-assisted SEM/EDS methods to test whether VSP profiles could be useful to associate shed fibers with a source carpet.Particles were harvested by washing and filtration onto polycarbonate filters. An SEM/EDS analysis protocol currently employed for environmental particle analyses was used, resulting in individual particle characterization based on fitting to reference spectra of 28 elements. Target Particle Types were defined based on the most abundant elemental profiles and used to bin the results for each specimen, resulting in a Target Particle Type profile.Within-carpet variability was assessed using Target Particle Type profiles from three different areas on each of nine carpets. Area profiles, defined from sets of ten fibers, were compared to profiles from individual fibers. Between-item variation was explored using a survey of an additional 12 carpets.Hundreds to thousands of VSP were found to routinely occur on individual carpet fibers. Their quantity and character was sufficient to associate fibers with their area of origin. Within-carpet variations showed roughly even distributions for most TPTs and between-carpet variations showed wide ranges in types and quantities of VSP.Environmentally acquired VSP showed clear potential to provide quantitative means to link carpet fibers with their area of origin. This finding is noteworthy, since such particles are acquired post-manufacture and are independent of characteristics determined by manufacture. More generally, VSP are ubiquitous, present on or in virtually any item, and there is the potential for linkages among items of any type based on adhering VSP. By way of example, the present work provides impetus for a fundamental change in the way that forensic trace evidence is conceptualized. Further fundamental research is indicated to better understand the underlying variability, usefulness and limitations of this approach. © 2015 Elsevier Ireland Ltd.


PubMed | Stoney Forensic Inc.
Type: | Journal: Forensic science international | Year: 2015

An effective trace evidence capability is defined as one that exploits all useful particle types, chooses appropriate technologies to do so, and directly integrates the findings with case-specific problems. Limitations of current approaches inhibit the attainment of an effective capability and it has been strongly argued that a new approach to trace evidence analysis is essential. A hypothetical case example is presented to illustrate and analyze how forensic particle analysis can be used as a powerful practical tool in forensic investigations. The specifics in this example, including the casework investigation, laboratory analyses, and close professional interactions, provide focal points for subsequent analysis of how this outcome can be achieved. This leads to the specification of five key elements that are deemed necessary and sufficient for effective forensic particle analysis: (1) a dynamic forensic analytical approach, (2) concise and efficient protocols addressing particle combinations, (3) multidisciplinary capabilities of analysis and interpretation, (4) readily accessible external specialist resources, and (5) information integration and communication. A coordinating role, absent in current approaches to trace evidence analysis, is essential to achieving these elements. However, the level of expertise required for the coordinating role is readily attainable. Some additional laboratory protocols are also essential. However, none of these has greater staffing requirements than those routinely met by existing forensic trace evidence practitioners. The major challenges that remain are organizational acceptance, planning and implementation.


PubMed | Stoney Forensic Inc.
Type: | Journal: Forensic science international | Year: 2015

The historical development, contributions and limitations of the two traditional approaches to trace evidence analysis are reviewed. The first approach was as generalist practitioner, looking broadly at an assemblage of many different particle types. The second was that of specialist practitioner, with attention focused on one specific particle type. Four factors have significantly impacted the effectiveness of these approaches: (1) increasing technological capabilities, (2) increasing complexity in the character of manufactured materials, (3) changes in forensic laboratory management, and (4) changing scientific and legal expectations. The effectiveness of each approach is assessed within the context of these changes. More recently, new technologies have been applied to some trace evidence problems, intended to address one or more limitations. This has led to a third approach founded on discrete, highly technical methods addressing specific analytical problems. After evaluating the contributions and limitations of this third approach, we consider the different ways that technologies could be developed to address unmet needs in forensic trace evidence analysis. The route toward effective use of new technologies is contrasted with how forensic science laboratories are currently choosing and employing them. The conclusion is that although new technologies are contributing, we are not on a path that will result in their most effective and appropriate use. A new approach is required. Based on an analysis of the contributions of each of the three exisiting approaches, seven characteristics of an effective trace evidence analysis capability were determined: (1) particle traces should be a major problem-solving tool, (2) there should be readily available, straightforward methods to enable their use, (3) all available and potentially useful particle types should be considered, (4) decisions to use them should be made in the context of each case, guided by what they can contribute to the case and how efficiently they can do so, (5) analyses should be conducted using appropriate technologies, (6) findings should be timely and directly integrated with case-specific problems, and (7) new technologies should be used to improve the overall effectiveness of the capability. Clearly new technologies have the potential to revolutionize forensic trace evidence, but just as clearly some of the traditional capabilities have been rendered ineffective, or lost entirely, by the way we have come to approach the problem. Having critically defined the current limitations of and the desired outcomes, the next focus should be consideration of alternative approaches that might achieve such a result.


PubMed | Stoney Forensic Inc.
Type: | Journal: Forensic science international | Year: 2016

On the contact surfaces of footwear loosely, moderately and strongly held particle fractions were separated and analyzed in an effort to detect different particle signals. Three environmental exposure sites were chosen to have different, characteristic particle types (soil minerals). Shoes of two types (work boots and tennis shoes) were tested, accumulating particles by walking 250m in each environment. Some shoes were exposed to only one environment; others were exposed to all three, in one of six different sequences. Sampling methods were developed to separate particles from the contact surface of the shoe based on how tightly they were held to the sole. Loosely held particles were removed by walking on paper, moderately held particles were removed by electrostatic lifting, and the most tightly held particles were removed by moist swabbing. The resulting numbers and types of particles were determined using forensic microscopy. Particle profiles from the different fractions were compared to test the ability to objectively distinguish the order of exposure to the three environments. Without exception, the samples resulting from differential sampling are dominated by the third site in the sequential footwear exposures. No noticeable differences are seen among the differential samplings of the loosely, moderately and strongly held particles: the same overwhelming presence of the third site is seen. It is clear from these results (1) that the third (final) exposure results in the nearly complete removal of any particles from prior exposures, and (2) that under the experimental conditions loosely, moderately and strongly held particles are affected similarly, without any detectable enrichment of the earlier exposures among the more tightly held particles. These findings have significant implications for casework, demonstrating that particles on the contact surfaces of footwear are rapidly lost and replaced.

Loading Stoney Forensic Inc. collaborators
Loading Stoney Forensic Inc. collaborators