Evidence analysis and processing

Based on the review of various forms of STR typing results and factors that impact the presence or condition of DNA on evidence, instructors in this installment of Probabilistic Genotyping of Evidentiary DNA Typing Results lay a foundation for the interpretation of forensic DNA typing results. The session will begin with background information on forensic DNA analysis, including terminology and mechanisms, to help all participants comprehend the material covered in this series.

This first webinar is an introduction to NMDID. Attendees will learn about the history of the database and the team that developed it. There will be a tour of the website, including data use agreement, “how to use” videos, descriptions of basic data types, and an introduction to the data dictionary.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on October 7, 2020. 

This webinar will provide an evaluation of the DEPArray™, a system that enables the identification, separation, and recovery of single cells or groups of cells from heterogeneous mixtures. The workflow described in this webinar will highlight the impact this instrument, with standard forensic processes, will have on processing sexual assault evidence and improving the success of single cell analyses.

Many working with genomic DNA can afford to lose large portions of it during its extraction without negatively impacting downstream analysis.  However, with work targeting highly degraded DNA sources, retention of every molecule can be key to successful analyses.   This webinar addressed the insufficient documentation of absolute efficiencies of extraction methods and the nature of DNA loss associated with the study of low copy number and degraded DNA samples.

This webinar introduced the importance of network forensics, which included capturing network traffic and reconstructing digital artifacts. Presenters discussed big data challenges, open-source tools, and the new toolkit FileTSAR.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on August 12, 2020.

This webinar focused on the use of PACE™, a method developed by Syracuse University, to perform artifact management and probabilistically predict the number of contributors (NOC) in forensic DNA samples. This is performed using a combination of biological modeling and machine learning, permitting high accuracy NOC calls (greater than 90%) of complex mixtures. It does so rapidly (seconds to minutes) without the need for high performance computing resources.

This webinar discussed intact low explosives analysis with a focus on microscopical methods. It covered terminology for explosives, the rationale of low explosives analysis for most crime laboratories, six categories of low explosives, and examples of three analyses using microscopical methods.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on July 16, 2020.

Residential structure fires are predominantly fueled by synthetic contents and commonly become ventilation-limited.  Therefore accounting for the impact of ventilation on fire is important. Examining flow paths within the structure can aide in fire pattern analysis.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on June 10, 2020. 

Using a typical OEM paint system, the PDQ Maintenance Team will walk through the best practices to efficiently use the database and spectral libraries to identify the most likely source of an unknown paint system. Details gathered from this process include manufacturing plant, year range, and models.

This webinar discussed the role of emergent technologies for both separation and detection techniques employed in chromatographic systems to increase selectivity for the identification of emerging drugs. Techniques include supercritical fluid chromatography, multi-dimensional liquid chromatography, multi-modal liquid chromatography, nano liquid chromatography, vacuum ultraviolet detection, and cold electron ionization mass spectrometry.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on March 19, 2020.

This presentation described, presented the results of, and discussed a recent black box study to establish an error rate estimate for palm comparisons. These results provided the first step in establishing the foundational validity of palmar comparisons, as defined by the President’s Council of Advisors on Science and Technology (PCAST) report.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on March 12, 2020. 

Improving the overall response to sexual assault includes understanding how touch DNA evidence impacts groping sexual assault cases. This webinar will illustrate the importance of these cases and highlight proposed guidelines for evidence collection.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on February 27, 2019.

This webinar built on the concepts presented in the webinar “The Time to Collect is Now: DNA Evidence in Groping Sexual Assault Cases” presented by Dr. Julie Valentine.

Given the vital role of medical examiners and coroners (ME/C) in recognizing emerging trends in drug overdose deaths, partnering epidemiologists with ME/C offices can greatly enhance the utility of the significant volume of data generated by medicolegal death investigation. Epidemiologists from three unique ME jurisdictions—North Carolina, New Mexico and Virginia—share their experiences with monitoring drug overdose deaths, trends observed, and how best to utilize ME/C data to inform public health policy.

After the Agriculture Improvement Act of 2018 (Farm Bill) was enacted in December 2018, many states rushed to make changes to their own laws to allow the hemp industry to grow and thrive in their jurisdictions. By removing hemp from the Controlled Substances Act, Cannabis sativa L. plant material with a concentration of delta-9-tetrahydrocannabinol less than 0.3% on a dry weight basis was no longer considered marijuana.

Molecular identification is advantageous for medicolegal death investigations involving entomological activity. This enables species-level identification of immature specimens necessary for estimating post-mortem interval and may be performed without specialized training or resources. The presenter describes a strategy effective for relevant species and demonstrates analysis of casework-type samples.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on December 2, 2021.

In this study, firearms examiners were asked to use traditional microscopic methods to identify unknown bullets to the appropriate barrels. Additionally, 3D scans of these bullets were used in a matching algorithm to find similarity scores between bullets. Error rates were determined and the potential for subclass carry-over among the barrels was evaluated. 

This webinar was presented by the NIJ Forensic Technology Center of Excellence on December 16, 2021.

This webinar will expand examiners' awareness of additional areas of interest for identification purposes. Two previously undocumented toolmarks were observed in Glock pistols and could potentially be used for other make/model pistols. These new toolmarks will expand an examiner’s ability to compare fired and unfired ammunition components to each other or to a suspect firearm.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on December 12, 2021.

This study assesses the production of subclass characteristics during the manufacturing of breech faces. Observations on how well subclass characteristics persist on manufactured breech faces with and without any finishing methods as well as the effect of the primer on the quality/quantity of the breech face impressions will be discussed.    

This webinar was presented by the NIJ Forensic Technology Center of Excellence on December 9, 2021.

The role of a death certificate has evolved from a legal record of death to a document used extensively by public and private entities to monitor the health of our nation. As the public health usage of death certificates continues to grow, it has become increasingly important to complete death certificates in a clear and consistent manner. This webinar will cover best practices for filling out death certificates in drug-related deaths.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on November 30, 2021.

With the increased prevalence of DART-MS in forensic laboratories comes an increased need for tools and resources. This webinar will highlight the new NIST/NIJ DART-MS Data Interpretation Tool (DIT), a freely available software tool that allows users to interpret DART-MS data resulting in improved presumptive screening of seized drug evidence. Other resources to assist with adoption and implementation of the DART-MS DIT will also be discussed.

This webinar was presented by the NIJ Forensic Technology Center of Excellence on October 21, 2021.