Aug 01 2017
Under the Microscope – Chantal Frégeau
The ISHI agenda is live and includes great talks from amazing speakers! While the forensic community is a tight-knit group, we can always get a little closer, right? With that in mind, we interviewed our speakers to preview their presentations and to get to know them a little better outside of their work. We’ve been posting their responses in a feature we like to call Under the Microscope.
Today, we’re chatting with Chantal Frégeau, who will be presenting New Portable Tool Capable of Triaging Evidentiary Samples at Crime Scenes to Provide Reliable Investigative Leads to Fast Forward Investigations during the General Sessions on Tuesday, October 3rd.
In what ways does triaging samples benefit an investigation? Are there any concerns with triaging samples at a crime scene?
In many cases, investigators currently utilize subjective criteria to determine the most pertinent exhibits to send in for DNA typing analysis. Triaging based on scientific tests offers a means to assist investigators in selecting the best samples for their first submission to the laboratory. They can determine samples that have DNA and assess which ones represent redundant DNA profiles. They may decide to retain those samples and send first other ones with higher % DNA scores (quality indicator). There is added importance when a forensic laboratory such as the RCMP manages demand by limiting the number of samples that can be submitted.
Triaging does not imply designating which exhibits to collect at the crime scene. Police investigators examine the scene as per their established procedures and following evidentiary sample collection, the determination of which samples to submit first for DNA typing analysis can be carried out at the crime scene or at the detachment. There may be concerns with overreliance on such a screening tool but no samples will be refused in the forensic laboratory if investigators suspect their sampling was suboptimal and may have produced 0% DNA scores or very low scores. All evidentiary samples will be retained by investigators and may be submitted at a later date if required.
What process was used to do this, and who performed the testing?
After a 2 year evaluation of the ParaDNA® Field Portable Unit and ParaDNA® Screening Test and ParaDNA® Intelligence Test at the RCMP forensic laboratory in Ottawa, two police agencies were approached to identify four investigators to take part in a customized training on how to properly use the ParaDNA® instrument, ParaDNA® test plates and ParaDNA® Sample Collectors. After processing 32 samples as part of three mock crime scene scenarios, and the completion of a proficiency test, they were deemed capable of processing evidentiary samples as part of the ParaDNA® field pilot project. For this pilot project, all samples subjected to the ParaDNA® testing regardless of results (with or without DNA, redundant profiles) were submitted to the forensic laboratory to monitor performance of the chemical tests and determine the reliability of the investigative leads provided by the ParaDNA® tests.
Were there any surprises that arose during the 5 month trial period?
Yes, there were a few. One of the reasons for running the field pilot project was to identify pros and cons of triaging samples at crime scenes/detachment. On the one hand, very quickly (75 min), investigators were able to:
- Identify duplicate samples from same contributor
- Link crime scenes
- Associate suspect with victim
- Track bleeders throughout a house (verify witness statements)
- Determine gender (exclude and change direction of investigation)
On the other hand, investigators indicated that triaging samples was more suitable at the detachment or police Identification laboratory rather that at the crime scene. This way, they could process a scene very quickly and not have to wait for the results to come out of the portable instrument. There were other surprises that will be revealed during my talk at ISHI 28!
How did you become involved with this project?
LGC Forensics approached the RCMP in 2009/2010 to determine our interest in having a tool to triage samples at crime scenes. We had noted that many samples processed in our three forensic laboratories had no DNA or produced redundant profiles with no meaningful results to assist investigators. We were hoping to improve our ability to assist investigators by filling our sample batches with samples that would show evidence of the presence of human DNA with good quality indicator to produce DNA profiles that could be uploaded to the National CODIS database or could lead to inclusions with forensic significance. We were interested in a tool to help investigators decide on samples to submit to the forensic laboratory first and those samples to retain for examination at a later date if needed.
The ParaDNA® portable instrument and ParaDNA® chemistry tests were evaluated during a 1 month pilot project in 2014 and the outcome was such that the RCMP purchased two instruments to further determine the limitations of the ParaDNA® System. This was followed by the field pilot project involving two police agencies.
What do you feel is the biggest challenge the forensics laboratories are facing today?
From a Biology/DNA discipline perspective, the highly sensitive STR kits and capillary electrophoresis-based detection instruments currently used for forensic DNA typing analysis very often generate complex mixtures from “touch DNA” exhibits brought in by the investigators. The biggest challenge remains the interpretation of those complex mixtures and the determination of the relevance of a contributor’s DNA profile derived from an exhibit to the crime that has been committed. Probabilistic software can assist with the interpretation of complex mixtures but determining how the genotypes were deposited remains challenging (relevance to the crime).
What do you think are likely to be the most exciting developments for the industry over the next couple of years?
I would have to say:
- The rapid and highly specific tests for the simultaneous detection of body fluids based on mRNA markers which will enhance the work currently performed in Evidence Recovery
- Massively parallel sequencing (MPS)-related products such as new kits, new interpretation tools, harmonized nomenclature for sequenced STRs (nominal alleles and sequence variants) and probabilistic software for MPS data.
What tips would you give to someone who is just starting out in the forensics field, or what’s the best advice you’ve ever received?
- Adopt good work ethics and follow the highest standards possible even though your work description or mandate does not include court appearances. Your work/performance will follow you throughout your career regardless of your position in an organizational chart.
- Consider yourself a permanent student. There is always something new to learn about DNA typing analysis or another discipline to broaden your knowledge. If you read the scientific literature on a regular basis you may be made aware of new methods and tips to adopt to enhance the work performed in your own forensic laboratories.
- Even though you may be performing routine/automated tests, always stay alert. Troubleshooting results that look abnormal will be made easier and understanding your results is very rewarding!
How did you become interested in forensics?
Pure chance! I received permission to attend an autopsy when I was a teenager (a friend of mine was assisting the coroner in a hospital) but my dad thought I would not survive the experience as I was only 16 years old so I missed my chance. Then I had the opportunity to visit the Centre of Forensic Sciences in Toronto in 1986 as part of an organized tour during an international scientific conference I attended and I was fascinated by the case studies showcased in the hallway. Midway through my Ph.D. at the University of Alberta in 1988, I was approached by the RCMP to join the Molecular Genetics Group in Ottawa for developing strategies for DNA typing analysis for human identification. I joined in 1991 and the rest is history!
When you’re not at work, what do you most enjoy doing?
I love to quilt but between work-related and family engagements, there is often little time to set up for this activity. Instead, I like to read history books while petting the family cats Darwin and Newton and I go to the gym for cardio-kickboxing, power up strength and power yoga classes.
For those who are on the fence about registering for the upcoming ISHI, please share your thoughts and reasons why they should attend.
ISHI highlights the latest trends in forensic DNA typing analysis. There are no parallel sessions ongoing simultaneously so you get to hear all the trendsetters directly. There is no need to split yourself in half and you are not missing out on any of the topics discussed. You can easily meet the presenters for networking purposes and the meeting is always well attended by forensic scientists that have been in the field since 1989! There is a lot of knowledge in that room at one time. Take advantage of it! You could meet forensic legends face to face…
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