Double Loop Podcast

In this episode, Eric and Glenn interview Caitlin Rough, a Masters student at the University of Western Sydney. Glenn saw Caitlin present at the IAFS conference back in November 2023. She comes onto the podcast to discuss her research project involving the interactions of latent prints (sebaceous residues) and blood. This work is near and dear to Glenn because of his previous work with Praska (see reference below). Caitlin discusses her observations with blood and a new twist of applying blood through various blood stain pattern mechanisms, such as swipes, spatter, pooling, and dripping. She observed the blood’s lipophobic reaction to the sebaceous ridge detail, which re-distributes the blood (often into the furrows of the mark). She also observed intermittent reactions of the blood with unknown components in the residue (as Glenn and Praska previously did). The guys discuss the implications of the research and next steps with Caitlin. Praska, N. and G. Langenburg. “Reactions of latent prints to expos

Eric and Glenn discuss their holiday parties and preparations, play another round of "Where in the Whorld?", and then interview a guest all the way from Sydney, Australia. Teneil Hannah, a PhD candidate at the University of Technology Sydney (UTS), joins the podcast to talk about some of her recently presented research on fingermark grading/quality scales. These are scales used by practitioners or researchers to evaluate the effectiveness of potentially new processing and visualization techniques to develop latent fingerprints. Whenever a laboratory is deciding to adopt a new treatment or change an existing one, the lab is expected to perform testing to evaluate the technique. There are a number of scales available to assess latent prints. Teneil walks us through what the most common scales are, who is using what, why are these scales important, and what modifications can be made to existing scales to improve their wide spread adoption and usage. References from Episode: CAST Scale Bandey, H.L. and Gib

Glenn Langenburg and Eric Ray spent the past few months traveling to conferences far and wide. This episode they catch up with each other on recent travels, stories from the road, and some of the presentations that they saw over the past few months. It's a laid-back episode, so join us for as we catch up with each other. (There's also a big reveal in this episode. Can you figure it out before Eric does?)

Eric and Glenn return with a super-sized episode where they trade courtroom stories. Glenn had two cases in 2023 where the judges and decisions were rather surprising. From being hurried, harried, and harassed, there were some oddball moments for Glenn. Eric similarly shared a few unusual court moments for him. We also encouraged our listeners to share their moments whether you were a witness, attorney or even as a juror, we’d like to hear your stories too!

Eric and Glenn share their adventures at the 2023 International Association for Identification conference held in August in National Harbor, MD in the Washington D.C. area. They discuss various lectures and workshops they attended. They also discuss Becca running the Double Loop Podcast “merch” booth and this year’s hot selling fingerprint tee-shirt. Becca interviews several attendees and gets some of the international flavor that is so much a part of each IAI annual conference.

Eric Ray and Glenn Langenburg are at the 2023 IAI conference in National Harbor, MD with Erin West and Ashley Church of Gap Science. They've developed a series of classes and an entire virtual conference dedicated to training for forensic supervisors and management. How many people should be reporting to one supervisor? What resources are available to forensic professionals? What if you're supervising a discipline that you're not trained in? Listen to the discussion and then join the FREE conference during Forensic Science Week.

To start the episode, Glenn tells Eric a story relating to Edmond Locard and Galdino Ramos, a doctor with an interesting connection to the history of fingerprints. Later in the episode the guys take on a listener question “What forensic discipline is the most reliable?” In order to address the question, they do a quick recap of various studies that attempt to estimate how lay people assess the reliability of different disciplines and contrast those data with black box error rate studies for each discipline, when available. Finally, Eric and Glenn discuss a new paper on DNA from Hicklin, et al. dealing with the accuracy of DNA analysts determining the number of contributors (NOC) to a DNA mixture. This study, and several other DNA papers, tie into the comparison between fingerprints and DNA, and which one they think is more “reliable”. All in all, a good general discussion for lay people and forensic scientists regarding what is meant by “reliable” in the eyes of jurors and what do these studies tell us a

Glenn Langenburg and Eric Ray bring the podcast to the California State Division of the IAI. Tom Busey joins the panel, and they discuss one of Tom's recent papers on an alternate method for calculating a fingerprint likelihood ratio. What if you didn't have to make decisions in fingerprint comparisons anymore? Big thanks again to the CSDIAI for inviting us to hold this panel discussion and for putting on a great conference.

Eric Ray and Glenn Langenburg discuss the recent article from Tom Busey - Tracking the growth of visual evidence in fingerprint comparison tasks. Examiners were shown features one at a time and asked to reach conclusions after each one. The study measured differences from the order of features revealed, their diagnosticity, and their clarity.

Glenn Langenburg and Eric Ray eventually discuss the results of the recent NIST Evaluation of Latent Friction Ridge Technology. But first there are a couple of detours. Glenn discusses recent testimony regarding questionable nanogram testing for the presence of drugs. Eric talks about the Cousins By Blood podcast and his involvement in that case. Once the discussion returns to NIST testing, the guys review the differences between the most recent tests and the previous round in 2012. Follow along with the discussion by viewing the results at: https://pages.nist.gov/elft/elft_1_x/results/

Eric Ray and Glenn Langenburg tackle three new Black Box / Accuracy studies from Austin Hicklin, et al and Noblis. Results from research into the accuracy of forensic handwriting comparison, footwear comparison, and bloodstain pattern comparison have been recently published. The guys break down the nuances of this research and how its similar and different from the latent fingerprint and palm print black box accuracy studies.

Glenn Langenburg and Eric Ray are joined by Alan McNamara to continue discussing the case that sent him to jail. Alan shares his story from the day the police first knocked on his door through the trials and appellate hearings. His first-hand account of this miscarriage of justice is an eye-opener for forensic scientists and for everyone with an interest in the criminal justice system anywhere in the world. Images and reports from this case are available at patreon.com/DoubleLoopPodcast.

Eric Ray and Glenn Langenburg continue their discussion of the Alan McNamara case from the UK. This time they start with the trial and then go through many of the expert witnesses that got involved in this case. Why do all the test lifts from the jewelry box have a wood grain in the background, but there is no grain in the evidence lift? Does the hook or Chinese character shape mean anything? How important is testimony about the homeowner's cleaning schedule? Can latent prints survive regular cleanings? Should there be questions about the accuracy of the latent print identifications to the homeowner? Eric then reads some of the internet comments that were made when the Alan McNamara case was first featured on the BBC's Panorama. Join us again on the next episode where we interview Alan McNamara.

Glenn Langenburg and Eric Ray discuss the case of Alan McNamara from the UK. In this episode we cover the details of the burglary and how the police focused on Alan McNamara. Despite many issues in the latent print evidence, charges moved forward. The prosecution's entire case was based on a single latent print with questionable documentation.

Eric and Glenn return from a hiatus to have a more relaxed catch-up episode. They share an adventure or two including the great Arizona Treasure Hunt that they participated in. Eric shares some experiences from the User Conference he worked. And finally the guys talk about the Double Loop Podcast booth experience at the 2022 Omaha IAI Educational Conference. They play a bunch of clips and recordings from our “Correspondent” Rebecca Coutant who was running the booth and playing “(Wo)Man on the Street” to get some attendee perspectives.

Eric and Glenn interview returning guest, and newly minted PhD, Dr. Henry Swofford on his recent paper, with co-author Prof. Christophe Champod: “Probabilistic reporting and algorithms in forensic science: Stakeholder perspectives within the American criminal justice system” (For Sci Intl Synergy 2020; https://doi.org/10.1016/j.fsisyn.2022.100220). The new article discusses interview responses from judges, prosecutors, defense attorneys, scholars, and forensic laboratory managers regarding their perspective on how to validate, implement, litigate, and communicate probabilistic tools and algorithms in American courts. They discuss different quotes and perspectives from the paper and relate that to their own experiences and observations. Henry also makes an important reference to a companion paper, that provides concrete recommendations and a strategy towards implementation by practitioners: “Implementation of algorithms in pattern and impression evidence: A responsible and practical roadmap” (FSI Synergy

Glenn Langenburg and Eric Ray sit down with Brianne Breedlove from Uncover Forensics to discuss online training and how things have changed in professional forensic training over the past few years. What are the challenges in this new format? What are the benefits that we could never do before? At the beginning Eric and Glenn finish off last episode's discussion on disclosure. Make sure to check out the new shirts and other merchandise at DoubleLoopPodcast.com.

Today, Eric and Glenn FINALLY review the Stephan Cowans case, a case of an erroneous identification from Boston where a fingerprint identification was critical evidence used to convict Cowans in 1998. This case is one of the few Innocence Project cases where there was an erroneous fingerprint identification but DNA was able to exonerate Cowans in 2004 (and the true source of the latent print was later identified). Eric and Glenn go through the major elements of the case and the subsequent review of the Boston Police Department Latent Print Unit by an external consultant. At the end, they discuss the critical improvements and advancements made in the wake of the error and why these cases are still important today to review and remember.

Eric Ray and Glenn Langenburg go round and around on the topic of how to disclose errors to defense. Should your errors be listed in your CV? Should they be disclosed to defense automatically? Only on request? They guys finish the episode reading an email from a listener about their experience with QC after an erroneous identification.

In this episode, the guys interview fingerprint examiner, multi-book author, and instructor, Hillary Moses Daluz . Hillary discusses her new book "Courtroom Testimony for the Fingerprint Examiner" (CRC Press; 2021). They discuss some of the difficult hot topics that examiners struggle with during testimony and how keep testimony training positive and optimistic.