The Time to Analyze is Now: DNA Evidence in Groping Sexual Assault Cases

The Time to Analyze is Now: DNA Evidence in Groping Sexual Assault Cases

This webinar originally occurred on January 29, 2020
Duration: 1.5 hours


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. The presenter discussed evidence collection and packaging for trace DNA, laboratory workflow, validation studies, and clean techniques to use when collecting or working with DNA.

The presentation began with a review of the case study and evidence collection concepts presented by Dr. Julie Valentine in the webinar “The Time to Collect is Now: DNA Evidence in Groping Sexual Assault Cases” presented on February 27, 2019.  We encourage participants to watch this webinar first to have a good foundation for what will be covered in the second webinar.  However, they may be watched independently of each other.

The foundation for this webinar was rooted in the many questions regarding lab processing of casework DNA samples that were asked during Dr. Valentine’s original presentation. This second webinar will target a multi-disciplinary audience and cover some basics of forensic DNA analysis and interpretation.

We discussed methods and clean techniques that are necessary for collecting and packaging trace DNA evidence.  Additionally, the presenter described clean techniques and laboratory set up to help prevent contamination when working with trace amounts of DNA.

The general steps of forensic DNA laboratory workflow will be covered, including extraction, quantitation, normalization, amplification, DNA separation and detection, and interpretation.  We also talked about the role validations play in helping determine the capabilities of the laboratory workflow and interpretation.  Knowing your equipment and how it functions with samples of all types is important for developing standard operating procedures for processing and interpreting DNA samples with low amounts of DNA.

Learning Objectives

  1. Describe clean techniques that should be used when collecting any type of biological evidence and clean techniques that can be employed in a forensic DNA lab to prevent contamination.
  2. Explain the basic steps of forensic DNA laboratory workflow and what the purpose of each step is.
  3. Understand the role validations play in forensic DNA analysis and interpretation.


  • Dr. Julie Valentine
  • Heather Mills

Funding for this Forensic Technology Center of Excellence webinar has been provided by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice.

The opinions, findings, and conclusions or recommendations expressed in this webinar are those of the presenter(s) and do not necessarily reflect those of the U.S. Department of Justice.

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