New Forensic Science Grant Reports Now Available

Through the National Criminal Justice Reference Service, NIJ has made available seven new final technical reports.

Application of Machine Learning to Toolmarks: Statistically Based Methods for Impression Pattern Comparisons (pdf, 99 pages)

Application of Raman Spectroscopy for an Easy-to-Use, on-Field, Rapid, Nondestructive, Confirmatory Identification of Body Fluids (pdf, 80 pages)

Establishing the Quantitative Basis for Sufficiency Thresholds and Metrics for Friction Ridge Pattern Detail and the Foundation for a Standard (pdf, 53 pages)

Filling a Critical Need by Establishing a Fully Functioning, CODIS Dedicated Laboratory (pdf, 101 pages)

Implementation of a DNA Triage and Analysis System Dedicated to Increasing the Throughput of High Volume Crimes in a Forensic Laboratory (pdf, 133 pages)

Taq Mutants Engineered for Forensics (pdf, 44 pages)

Use of Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) Methods for the Analysis of Small Particles Adhering to Carpet Fiber Surfaces as a Means to Test Associations of Trace Evidence in a Way that is Independent of Manufactured Characteristics (pdf, 77 pages)

Additional details for each report are listed below. These reports are the results of NIJ-funded projects but were not published by the U.S. Department of Justice.

Title:
Application of Machine Learning to Toolmarks: Statistically Based Methods for Impression Pattern Comparisons (pdf, 99 pages)

Authors:
Nicholas D. K. Petraco, Ph.D., City University of New York; Helen Chan, B.A., City University of New York; Peter R. De Forest, D. Crim, City University of New York; Peter Diaczuk, M.S., City University of New York; Carol Gambino, M.S., City University of New York; James Hamby, Ph.D., International Forensic Science Laboratory & Training Centre; Frani L. Kammerman, M.S., City University of New York; Brooke W. Kammrath, M.A., City University of New York; Thomas A. Kubic, M.S., J.D., Ph.D., City University of New York; Loretta Kuo, M.S., City University of New York; Patrick Mc Laughlin, City University of New York & New York City Police Department; Gerard Petillo, B.A.; Nicholas Petraco, M.S., City University of New York & New York City Police Department; Elizabeth W. Phelps, M.S., City University of New York; Peter A. Pizzola, Ph.D., New York City Office of the Chief Medical Examiner; Dale K. Purcell, M.S., City University of New York; Peter Shenkina, Ph.D., City University of New York

Authors' Abstract:
Over the last decade, forensic firearms and toolmark examiners have encountered harsh criticism that there is no accepted methodology to generate numerical “proof” that independently corroborates their morphological conclusions. This project strives to answer that criticism and focuses on:

a. The collection of 3D quantitative surface topographies of toolmarks by confocal microscopy;
b. Identification of relevant modern multivariate machine learning methods for tool-toolmark associations and estimations of identification error rates; and
c. Dissemination of toolmark surface data and software generated for the project to aid further research.

A database was assembled which consists of 3D striation and impression patterns on Glock fired cartridge cases, screwdriver and chisel striation patterns. The database is now available to registered users. Statistical studies were carried out on a large portion of the primer shears (cartridge cases) and screwdriver striation patterns collected thus far. Principal component analysis, canonical variate analysis and support vector machine methodology was used to objectively associate these toolmarks with the tools that created them. Estimated toolmark identification error rates were on the order of 1% using these algorithmic methods. Conformal prediction theory was used to assign confidence levels to each toolmark identification and is suggested as a useful measure in gauging the quality of a toolmark “match” for a multivariate classification system. The findings of this objective and quantitative scientific research reinforce the general conclusions codified in the AFTE theory of identification.


Title:
Application of Raman Spectroscopy for an Easy-to-Use, on-Field, Rapid, Nondestructive, Confirmatory Identification of Body Fluids (pdf, 80 pages)

Author:
Igor K. Lednev, University at Albany, SUNY

Author's Abstract:
According to the major goals of this project, a novel method was developed for the nondestructive, confirmatory identification of body fluid traces based on Raman spectroscopy combined with advanced statistics. Our prior hypothesis that the Raman spectroscopic signature of each body fluid is unique and can be used for identification purposes was confirmed. A library of Raman signatures for various body fluids, specifically blood, semen, vaginal fluid, saliva and sweat was built and software for the automatic identification of an unknown sample was developed. The method was expanded to include body fluid stains on various substrates and contaminated stains.

Human body fluids were collected from anonymous groups of donors. The donors’ age, race and gender were disclosed to assure the required diversity and sample size. Samples of each body fluid were obtained from donors representing five races, including: Caucasian, African American, Asian, Hispanic and Native American. Dry traces of body fluids were tested using Raman microscope equipped with a computer-controlled stage for rapid mapping. It was found that dry traces of body fluids are intrinsically heterogeneous meaning that Raman spectra measured from different spots varied significantly. We proposed a new approach to identification by utilizing multidimensional spectroscopic signature to account for sample heterogeneity and variations with donor. Our developed software algorithms compare experimental Raman spectra with the library of Raman signatures, providing quantitative measures of similarity. It was demonstrated that an unknown stain of a pure body fluid can be identified with near 100% accuracy provided that good quality Raman spectra are acquired.

We demonstrated that mixed samples can be identified through automatic mapping if two body fluids are not thoroughly mixed. Thoroughly mixed samples can be identified using support vector machine (SVM)-based methods. Specifically, SVM-based method was able to identify a small contribution (2-5%) of thoroughly mixed semen in blood and blood in semen samples. As a specific objective of this project, the problem of substrate interference was also explored. We demonstrated that dry traces of blood and semen can be identified successfully on several substrates of practical importance.

Overall, this study demonstrates great potential of Raman spectroscopy for the nondestructive, confirmatory identification of body fluid traces, including stains on various substrates and contaminated mixtures. Additionally, a program was developed for the automatic identification of body fluids in dry mixtures.


Title:
Establishing the Quantitative Basis for Sufficiency Thresholds and Metrics for Friction Ridge Pattern Detail and the Foundation for a Standard (pdf, 53 pages)

Authors:
Randall S. Murch, Virginia Tech; A. Lynn Abbott, Virginia Tech; Edward A. Fox, Virginia Tech; Michael S. Hsiao, Virginia Tech; Bruce Budowle, University of North Texas

Authors' Abstract:
The purpose of this two-year project has been to address the need for a sound, quantitative basis for assessing the quality of fingerprint images. Latent prints, in particular, can be problematic because they are often partial, smudged, and otherwise distorted. Prints of sufficiently high quality routinely allow for identification (i.e., originates from one known source) or exclusion (i.e., could not have originated from a reference source). However, image quality problems related to identifiable Level 1, 2, or 3 details can be a major source of uncertainty and potential error, or may contribute to a (sometimes incorrect) determination of no conclusion. An ability to assess fingerprint image quality therefore represents a crucial step in reaching correct determinations.

The high-level goal of this cross-disciplinary collaboration has been to derive a scientific foundation for measurement of fingerprint image quality, particularly for latent prints. The objectives of this effort have been the following: to make a significant contribution to increasing accuracy, reliability, repeatability, verification, defensibility, and uniform assessment of fingerprint pattern analysis and practice; to provide a demonstrable and defensible basis for engagement of the relevant practitioner and stakeholder communities to incorporate and accept standards into friction ridge pattern analysis, reporting, and use; to provide for substantial improvements to training, proficiency testing, quality assurance, and control (quality management) that are more consistent across the forensic science community; to incorporate metrics that can be documented into the ACE-V or other accepted friction ridge examination methods; to provide the foundation for the development of novel technology aids for human examiners to automate fingerprint pattern image quality determinations; and to provide the basis for image quality determination (accept-reject) that also can be applied with automated fingerprint systems at the point of capture.

The work has been motivated in part by the Daubert ruling (Daubert v. Merrell Dow Pharmaceuticals, 1993), as well as by conclusions drawn in the subsequent study by the National Academy of Sciences, Strengthening Forensic Science in the United States: a Path Forward (2009). It is reasonable to expect scientific validity when using friction-ridge information for identification or exclusion.

The researchers on this project have followed an experimental approach, testing theoretical concepts through their application to actual images, and then performing statistical validation of the results when possible. Several image databases have been used, containing rolled prints, flat (plain) prints, and latent prints. The researchers also have obtained prints in the laboratory, using latent lifting methods as well as a dedicated live-scan imaging device. Furthermore, the researchers have digitally altered images of actual prints in order to determine drop-off points, that is, thresholds at which an area of friction ridge or feature can no longer be reliably used for identification. Metrics to quantify the effect on image quality have been developed. From these studies, quantitative thresholds have been established for unbiased selection and for use of Level 2 detail, in which both minutia and friction ridges have been incorporated into our formulation.

In conclusion, the results obtained have been noteworthy. First, our hierarchical representation of relations among minutia and friction ridges offers a unique and powerful way for fingerprint search and comparison. In addition, it allows for the mining and detection of unique and rare features that can be extremely useful when drawing statistical likelihood of a given feature. We have also been successful in developing techniques to enhance the accuracy of extraction of ridges and minutia from a print using novel filtering techniques. We developed parallel implementations of our algorithms on a low-cost general purpose graphics processing unit (GPU) and achieved a significant speed-up. Finally, we have successfully created a database of synthetic fingerprints.


Title:
Filling a Critical Need by Establishing a Fully Functioning, CODIS Dedicated Laboratory (pdf, 101 pages)

Authors:
Bill Gartside, Scott McWilliams

Authors' Abstract:
Wyoming State Statutes require the establishment and administration of a Wyoming State DNA Database and allows for participation in the National DNA Index System (NDIS). Historically in Wyoming, offender sample processing was being performed only by outsourcing offender samples to private laboratories using funding from the National Institute of Justice (NIJ). There was no equipment or laboratory space at the Wyoming State Crime Laboratory (WSCL) dedicated for CODIS sample profiling. We sought to address this mission critical need by the establishment of an automated, fully functioning CODIS dedicated laboratory. The NIJ funding through this grant allowed for the purchase of the laboratory test equipment necessary to achieve this goal.

The Wyoming State Legislature funded the construction of a state laboratory building complex in Cheyenne Wyoming, which was completed in November 2010. Included in the building complex is over one thousand square feet of space dedicated to CODIS laboratory and CODIS administrative functions. The goals and objectives of this project were to establish and increase the capacity of the WSCL CODIS Unit in order to meet the current and anticipated critical need for a highly automated fully functioning CODIS Laboratory by the procurement of dedicated CODIS Unit laboratory equipment.

Wyoming Offender samples are currently being collected and archived with Bode buccal collectors. The method that was validated and is currently in use at the WSCL for convicted offender sample processing uses BSD punchers for the robotic placement of 1.2mm punches in a 96 well plate. Punches are directly amplified without extraction or quantitation with Applied Biosystems (AB) Identifiler Plus kits. Amplification set-up is performed using a Qiagen QIAgility robot and amplification is performed in an AB 9700 thermal cycler. Analysis is performed using an AB 3500 eight-capillary genetic analyzer and AB GeneMapper ID-X data analysis software. The process is managed by ‘Database Manager’ an internally developed Excel-based Visual Basic for Applications (VBA) information management system which facilitates all aspects of the methodology.

The current first pass success rate for convicted offender samples is greater than 95%. Samples which are not initially successful and difficult samples are re-routed through the WSCL Casework DNA laboratory for a more conventional analysis which includes DNA extraction and quantitation.

All convicted offender samples are currently being processed at the WSCL using the CODIS laboratory established under this solicitation. Sample backlog has been significantly reduced: The turnaround time from sample receipt to database entry has improved from more than 2 years to less than 60 days from receipt until CODIS entry.


Title:
Implementation of a DNA Triage and Analysis System Dedicated to Increasing the Throughput of High Volume Crimes in a Forensic Laboratory (pdf, 133 pages)

Authors:
Elizabeth Thompson, Mary Hong, Camille Hill, Scott Scoville

Authors' Abstract:
A two-fold approach was adopted in Orange County, California to improve the efficiency and capacity of the Orange County Crime Lab (OCCL) to screen and process property crime DNA evidence to meet the increasing demand of County law enforcement investigators for property crime DNA analysis. This Property Crime DNA Program featured the utilization of a sophisticated DNA case submission and triage system and the adoption of a team approach to process biological evidence from property crimes using a newly created high volume crime DNA platform.

The Property Crime Triage System that included the utilization of a new case submission process was cooperatively developed and implemented by the OCCL and the Orange County District Attorney’s Office (OCDA). Together, members from both entities evaluated DNA analysis requests submitted to the lab from County police agencies. While forensic DNA analysts examined property crime DNA analysis requests from a scientific basis; prosecutors evaluated the same requests from a legal perspective.

The OCCL DNA Section developed and implemented the “OCCL Property Crime High Volume DNA Platform.” DNA analysts were assigned to a team that was devoted exclusively to the processing of property crime DNA samples using a customized scheduling system and a highly automated DNA processing platform. Team members worked together to screen, analyze and expeditiously deliver property crime scene DNA sample results each week.

The Property Crime High Volume DNA Platform teams utilized both existing equipment and new instrumentation purchased using 2009 DNA Unit Efficiency Improvement Grant funds. New purchases included two types of extraction robots, two different liquid handling robots and a multi-capillary genetic analyzer. The equipment and instrumentation were organized into a Property Crime DNA Analysis Line designed to process hundreds of DNA property crime samples each week and capable of accommodating up to three property crime DNA teams.

With the triage method and Property Crime High Volume DNA Platform in place, it was anticipated that no more than 10 workdays would pass from the time a completed submission packet was received until analysis was commenced (a completed submission packet included police reports, supplemental forms and assurances that necessary elimination standards were collected). Since DNA analysis was expected to take no longer than 15 workdays, it was hoped that law enforcement would have results for property crime cases within 25 workdays from the time the request for DNA analysis was submitted. This goal was not achieved within the time constraints of the project. Instead, the average turn-around-time to provide DNA results to police investigators was 74 workdays.

Orange County believed that the implementation of the new case submission process, the triage method and the OCCL Property Crime High Volume DNA Platform would not only increase the capacity of the lab to process property crime samples but would also allow major case analysts to devote more time to the processing of violent crime cases. The OCCL, therefore, expected to also significantly reduce the average turn-around-time from submission of a request to a completed report for violent/major cases.

The implementation of the new case submission process, the Triage System, and Property Crime High Volume DNA Platform reduced the average turn-around-time for the acceptance and DNA analysis of both property crime cases and violent/major offense cases. (Property crimes are considered “high volume” crimes because they are crimes with the highest recorded frequency and recidivism rates. A violent/major crime is any crime where the accused uses or threatens the use of violent force on the victim, such as homicide, rape or assault.) At the start of this project, the average turn-around-time for property crimes, from submission of a work request until completion of the lab report, was approximately 125 workdays and the average turn-around-time from submission of a work request to completed report for violent/major offenses was approximately 89 workdays. OCCL Property Crime High Volume DNA Platform statistics from April 1, 2011 to March 31, 2012 indicate that the average turn-around-time for property crimes, from submission of a work request until completion of the lab report, is now 114 workdays compared to 125 workdays at the start of the project in October 2009. The average turn-around-time from the submission of a work request to a completed report for violent/major offenses is now 62 workdays compared to 89 workdays at the end of 2009.


Title:
Taq Mutants Engineered for Forensics (pdf, 44 pages)

Author:
Milko Kermekchiev, Ph.D., DNA Polymerase Technology, Inc.

Author's Abstract:
Major problems with PCR-based forensic tests are false negative results and low sensitivity caused by residual blood, soil or other PCR inhibitors present in the sample. We proposed to apply our novel genetically-engineered mutants of Taq DNA polymerase, highly resistant to PCR inhibitors, to direct DNA analysis of forensic samples. In many cases, this approach can eliminate the need to purify DNA prior to PCR and decrease the time, lower the cost, and increase the efficiency of forensic DNA testing. In order to achieve this goal, we set the following objectives:

1. Develop and optimize a protocol without the DNA extraction steps for direct PCR-based typing of the human STR loci from crude samples containing blood and soil using our novel OmniTaq and Omni Klentaq enzymes.
2. Develop specific PCR enhancers to improve the detection sensitivity of crude samples.
3. Test the resistance of OmniTaq and Omni Klentaq to PCR inhibitors derived from substances other than blood or soil, such as urine, semen, hair/melanin, tannins, indigo dye, bones, muscle tissue, saliva, and feces/bile salts, and extend the application of the mutant enzymes to testing crude samples of these substances.
4. Formulate and optimize blends of OmniTaq and Omni Klentaq with some members of the Y-family thermophilic polymerases with improved performance on damaged DNA.

In our preliminary tests we found that our cold-sensitive hot-start mutant enzyme, Cesium Taq, performs very well in STR typing, while the Omni Klentaq tends to generate more stutters, therefore we gave a preference to exploring CesiumTaq, along with OmniTaq enzyme. Before we applied our enzymes and enhancer cocktails to the multiplex DNA typing, we performed a series of systematic testing of various known PCR inhibitors, including blood, treated or untreated with anticoagulants, soil / humic acid, urine /urea, semen, bile salts, tannins, melanin and indigo dye in monoplex PCR of human gene targets (such as some of the STR alleles, CCR5, beta-actin, DNMT ) with OmniTaq and CesiumTaq enzymes, in order to determine the range of tolerance of the mutant enzymes to the particular inhibitor. Along with this line, we tested various formulations of our 3/4 components PCR enhancer cocktails (PECs) , to find the most efficient formulation for each PCR inhibitor tested. Our PECs, which were recently published, typically play a double role, they act as a general PCR enhancer, improving the yield, sensitivity and specificity, especially with tough, GC-rich DNA templates, and they also help overcoming PCR inhibition, thus facilitating DNA amplification from crude samples. The Y-family polymerases, mentioned in Objective 4 and obtained from the NIH through an evaluation license, unfortunately did not meet our performance criteria, showing poor activity and stability with inconsistent results, therefore we dropped this direction from the project. We successfully developed protocols for STR genotyping of crude samples containing the above mentioned inhibitors, skipping the DNA extraction steps. Some of the specimens were provided from our sub-contractor, Bode Technologies. These protocols predominantly utilize our mutant enzymes Omni Taq and CesiumTaq, optimized PCR buffers, and enhancer cocktails, PEC and PEC-Plus, each of them optimized for a certain group of crude samples. Our protocols are compatible with the primers and cycling conditions of both PowerPlex 16 HS (Promega) and AmpFlSTR Identifiler Plus (Life Technologies) kits, therefore they do not require any extra steps or changes in the established protocols, except that specific components of the master mix provided in these commercial kits are replaced by our components. We present results showing that in comparative tests of direct STR typing with challenging crude samples our protocols outperform significantly the AmpFlSTR Identifiler Plus kit, and to some extent the PowerPlex 16 HS kit.


Title:
Use of Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) Methods for the Analysis of Small Particles Adhering to Carpet Fiber Surfaces as a Means to Test Associations of Trace Evidence in a Way that is Independent of Manufactured Characteristics (pdf, 77 pages)

Authors:
David A. Stoney, Ph.D., Stoney Forensic, Inc.; Paul L. Stoney, MBA, Stoney Forensic, Inc.

Authors' Abstract:
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 (now routinely exploited through DNA analysis). We move about in a soup that is a combination of VSP that provides an extraordinary, largely untapped resource for forensic associations and source attribution. This project was an initial, highly successful effort to exploit VSP for one specific application.

An innovative instrumental trace evidence analysis approach was developed and tested for the recovery and quantitative SEM/EDS analysis of VSP adhering to the surfaces of carpet fibers – one of the most common types of trace evidence examined in crime laboratories.

Program goals were: (1) to develop methods to quantitatively remove VSP from carpet fibers and prepare them for SEM/EDS analysis, and (2) to exploit existing computer-assisted SEM/EDS methods to test whether the resulting VSP profiles are useful to quantitatively associate shed fibers with a source carpet. Specific program objectives were to:

  • Develop suitable methods as described
  • Use these methods to determine VSP profiles within source carpets
  • Analyze VSP adhering to single fibers from the source carpets, and determine if their VSP profiles were consistent with an unbiased statistical sampling from the source carpet
  • Explore between-item variation for VSP profiles using a broader qualitative survey of carpets
  • Appropriate methods were developed and used to assess within-carpet variability using VSP from three different areas on each of nine carpets. Carpet area VSP profiles were defined by a set of ten carpet fibers and the profiles of individual fibers from these areas were compared. Between-item variation was explored using a survey of VSP profiles on an additional 12 carpets.

Program goals and objectives were met. The regular occurrence of hundreds to thousands of VSP on individual carpet fibers was demonstrated. The quantity and character of VSP was sufficient to associate fibers with their carpet area of origin. The hypothesis of a strictly quantitative relationship among VSP, as measured using environmental particle profiles, was strongly rejected. These environmental particle profiles were found to be unsuitable to assess VSP variability. An alternative method was developed based on Target Particle Types (TPTs) defined by their elemental profiles as measured by computer-assisted SEM/EDS. Within-carpet and between-carpet variations showed a roughly even distribution for most TPTs and between-carpet variations showed a wide range in types and quantities of VSP.

The usefulness of VSP to link of carpet fiber evidence has been established. There is now a clearly achievable potential to use VSP for independent, quantitative testing of the common origin of carpet fibers. To unlock this potential, a set of follow-on research steps have been outlined and are ready to be undertaken.

The specific application of VSP to carpet fibers is ready for development, but the proof of principle resulting from this research is of much broader significance for the future of trace evidence analysis. It is a breakthrough providing the impetus and direction for a fundamental change in the way that forensic trace evidence is conceptualized, analyzed and used in the criminal justice system. The results of this research are likely extendable, with minor modifications, to other trace evidence types, and are expected to contribute significantly for those types of trace evidence that have long been considered of low evidential value. 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 that on virtually any item of physical evidence. 

 
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Forensic Podiatry (Part Two of Two)

THE DISCIPLINE of forensic podiatry—or, in other words, the examination of pedal evidence—has progressed significantly over the past ten years. It is no longer a question of “What can you do with a footprint?” but rather, “Who can we use to evaluate the footprint?” Cases involving pedal evidence, especially bloody footprints and issues of determining shoe sizing or fit issues compared to questioned footwear, have become more common over the past two or three years.

Read more...