Putting All of Your Evidence on a Bagel: Why Everything Does Matter

Today’s guest blog is written by Nancy Dinh, Senior Forensic Scientist at the Forensic Analytical Crime Lab. Reposted from the ISHI Report with permission.


Some readers may be familiar with the film “Everything Everywhere All At Once” (EEAAO). Briefly, it’s a story of a woman named Evelyn who works at a laundromat with her husband and they both share a rebellious teen daughter. Evelyn has a complicated relationship with every person in her life, including herself, and each of these relationships is explored through alternate universes. Eventually with the help of every person she interacts with, she is able to find the key to happiness through these otherworldly experiences and learn to live her life in the real world with a greater understanding of people and her surroundings. I watched this movie recently and it inspired me to talk about work.



Much like Evelyn, we as forensic scientists started in our own seemingly normal lifepaths, but as we became more involved in our forensic careers, we became experts at traversing between the normal real world and the alternate world that is casework. Every day we enter multiple alternate universes where we play detective, investigating crimes in order to understand how to sample our evidence, and we do the evidence justice by getting as much information as we can from it. However, this requires many resources that are hard to obtain, and when our focus shifts from finding truth in evidence to pumping out as much casework as possible to make someone happy regardless of the quality of the work, the motivation to get the resources we need wanes. What we once found to be enchanting about this field gets lost in the weeds of workplace politics, outside pressures that we as individual analysts are no match for, and the drudgery that standard 9 to 5 work inevitably becomes.


My work situation is unique in that most of the work that I do is for the defense, and in most cases, DNA work has already been completed on some or all of the relevant evidence by a state or local agency’s lab. I review bench notes and reports produced by other labs, assist attorneys in understanding the data and conclusions, and sometimes I provide recommendations for further testing. I then might re-examine items or look at items that were never examined before and perform DNA testing. Being a part of the investigative team means contributing to a story – whether it be by translating DNA-speak into layman-speak or prodding at evidence in an attempt to fill in some of the gaps in the storyline. Ultimately, the goal is to find truth in DNA evidence. The cases that I share below are not meant to be disparaging to other experts; we’re all on the same team and I am hoping that hearing some of these stories will lead to meaningful discussions about the areas in which we can all improve.


Case #1

The first case is a sexual assault/murder cold case – believed to be part of a string of serial crimes that occurred in the mid-1980s – wherein the victim was found deceased along the highway. Little was known about the victim. A sexual assault kit collected from the victim was first examined and tested in 2003. Semen was detected on the victim’s vaginal swab but the DNA result was determined to be ineligible for comparison to known samples due to limited genetic information. Semen was not detected on the anal swab and subsequent revisits to the evidence in this case did not include the anal swab likely because the swab was consumed during the initial testing and the result was not informative.


In 2020, my lab received the victim’s sexual assault kit and among the specimens that remained was an empty glass vial labeled “anal swab”. I noticed there was residue along the inside of the anal swab tube, so I decided to give it a shot and swab the residue despite previous findings (or lack thereof). I examined my sample microscopically and discovered sperm, which meant that there in fact was semen on the anal swab. And just like that, the anal swab that was once an unremarkable pawn in this case was now promoted to King. I took my sample through DNA testing and generated a result that was a mixture of at least two males – a major contributor and at least one minor contributor – and submitted this result to CODIS for search. Unfortunately, the anal swab sperm result was not eligible for CODIS upload; however, the case is still being investigated and potential suspects are continually being compared to this profile to this day.


From this case we can see that the true results were not discovered during the initial round of testing and that those results likely had an impact on all subsequent examinations of the evidence. If there’s anything I learned from my years of re-testing items, it’s that it’s best to treat the item as if it had never been tested before. Make your own observations and come to your own conclusions despite previous results because your findings may be different – and in this case the opposite – of what someone else found. For almost 40 years, the DNA evidence in this case did not provide any leads, but with a little bit of ingenuity (and some determination), we were able to uncover very useful information.


Case #2

In a 1997 homicide case, a man was shot and killed outside of a nightclub during the course of a robbery. Witnesses identified the suspect as having worn an oversized football jersey which he had discarded in a bush while fleeing the crime scene. An anonymous caller phoned police and accused a man – who we’ll refer to as John – of being the gunman. John was ultimately convicted of the crime in 1998. Postconviction DNA testing at a private lab in both 2009 and 2014 focused on testing the football jersey for wearer DNA from the suspect. These examinations focused on areas that might be in contact with the skin of the wearer and areas of potentially high friction, such as the inside neck and the inner cuff areas. In 2009, the lab was unable to obtain any DNA results. In 2014, the lab determined the DNA results were far too limited and complex for interpretation.


In 2020, my lab reviewed the previous work and opined that the approach to sampling the jersey for wearer DNA was not appropriate because jerseys are typically worn over other layers of clothing and do not make as much contact with skin in the same way that a fitted t-shirt or a long-sleeve button up might. In our re-examination of the jersey, we attempted to look for any biological deposits that could have come from other types of contact, such as wiping of the nose or mouth. Biological stains were located on both outer sleeves of the jersey. DNA testing of stains from both sleeves revealed a unique male DNA contributor. John was eliminated as this male. The profile was searched in the CODIS database without success. Continued investigation into the case by law enforcement led to the identification and arrest of the actual gunman in 2022. In 2023, twenty-five years after his conviction, John was formally exonerated.


These are just two of hundreds of cases we’ve encountered in our laboratory alone. These oversights and/or omissions are not localized to any specific lab. They span different counties and states, from state-level to federal. Many causes and factors are culpable, from limited resources and unreasonable outside pressures to inadequate training and experience. My hope is that we can all take a step back and re-evaluate our laboratory practices and think about how we can all enhance the way we perform our work. Seemingly small errors have the potential to create big problems: A perpetrator could remain free to commit additional crimes, or the wrong person could be behind bars for a crime they did not commit.


Unlike EEAAO where the proverbial everything bagel that holds all of our hopes and dreams is regarded as something that does not matter, in the forensic DNA world where the everything bagel metaphorically represents every facet of a case, everything does matter. The outcome of a case hinges upon the meticulousness, the creativity, and the diligence of the work put into the process.


Remind yourself of why this particular line of work was and continues to be so important to you and to your community and why it’s important to always try to uncover the actual truth in the evidence. In an alternate universe where we weren’t forensic scientists, we probably would have really liked just doing laundry and taxes; but in this life we have now, it is our responsibility to continue asking questions and to aim to be better stewards of justice and truth because the lives of other people in this particular universe depend on it.