Podcast
Double Loop Podcast
Hosted by Glenn Langenburg and Eric Ray · EN
Whether you're a practicing Latent Print Examiner or you're interested in forensics and true crime, the Double Loop Podcast is a weekly show featuring Glenn Langenburg and Eric Ray discussing latent print topics, current events in forensic science, the newest research articles, interesting guests, and analysis of notable cases from a forensic scientist perspective.
19episodes
Episodes
Newest firstAll episodes
Episode 291 - Mundane Obstacles to Developing a Stats Model
May 401:26:21Tap to summarizeEric and Glenn start the episode with a listener email and then play a numbers themed game of Regional Quirkisms. For the topic of this episode, the guys discuss a 2025 paper from Simon Cole and Justin Sola titled "First impressions matter: Mundane obstacles to a forensic device for probabilistic reporting in fingerprint analysis". The article discusses practical and realistic obstacles and hurdles to developing a validated, accepted, and commercially-available statistical model for fingerprint evidence. The article takes the novel view that most sources cite either "practitioner disinterest" (or worse: practitioner rejection) or lack of push and influence from the Courts, Daubert challenges, or Authoritative bodies. However, once you remove those two obstacles and assume examiner 'buy-in' and Courts pushing for empirical data over subjective examiner expertise, what 'mundane' obstacles exist that most people don't realize or think about? The article discusses a number of surprising, non-trivial obstacles that have a huge influence on the state of statistical model development in the field today. Article: Cole, S.A.; Sola, J.L. First impressions matter: Mundane obstacles to a forensic device for probabilistic reporting in fingerprint analysis. Social Studies of Science (2025), 55(5): 683-710. https://doi.org/10.1177/03063127251333074
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Episode 290 - Review of a Bias Research Paper
Apr 601:18:43Tap to summarizeIn this episode, the guys start off with some Michigan Regional Quirkisms. They then review a 2024 paper titled "The effects of cognitive bias, examiner expertise, and stimulus material on forensic evidence analysis" by Michelle Pena, Stephanie Stoiloff, Maria Sparacino, and Nadja Schreiber Compo, from the Journal of Forensic Sciences (2024; 69:1740-1757). The research paper provided lay participants (students) and fingerprint expert participants with images of ground truth, matching and non-matching fingerprint pairs. The researchers controlled the exposure of the participant to contextual case information. Lay participants made a number of errors and seemed to be more impacted by case information compared to experts in these trials. Glenn and Eric discuss why that might be and discuss and compare other studies that might be relevant on this topic. Article: Pena MM, Stoiloff S, Sparacino M, Schreiber Compo N. The effects of cognitive bias, examiner expertise, and stimulus material on forensic evidence analysis. J Forensic Sci. 2024 Sep;69(5):1740-1757. doi: 10.1111/1556-4029.15565. Other Articles Discussed: Tangen, J. M., Thompson, M. B., & McCarthy, D. J. (2011). Identifying fingerprint expertise. Psychological Science, 22(8), 995–997. https://doi.org/10.1177/0956797611414729 Langenburg, G., Bochet, F., & Ford, S. (2014). A Report of Statistics from Latent Print Casework. Forensic Science Policy & Management: An International Journal, 5(1–2), 15–37. https://doi.org/10.1080/19409044.2014.929759
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Episode 289 - Angela Tonietto Interview - Palm Patterns
Feb 2201:04:33Tap to summarizeGlenn Langenburg and Eric Ray interview Angela Tonietto about her recent article on the frequency of patterns in palm prints. ("Patterning in the Distal Portions of the Palms as a Key to Palm Print Identification". 2025, 75-3, p.274.) The research analyzes the frequency of loops and deltas in the interdigital area and compares the results to past research. (Link mentioned in episode: https://demo.hugin.com/example/FingerprintEvidence)
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Episode 288 - Close Non-matches
Jan 2101:21:03Tap to summarizeHappy New Year 2026! The boys are back in town, with a new game: Regional Quirkisms. After discussing Minnesota quirkisms, the guys answer a listener question from Ireland: "What's the most number of corresponding minutiae that you have seen from two impressions from different sources?". This leads to a deep dive on close non-matches. The guys share their tips, tricks, and red flag warnings for dealing with close non-matches. They discuss a few examples and talk about the relevant research on this topic.
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Episode 287 - IAI 2025 Review
Dec 1301:29:22Tap to summarizeEric Ray and Glenn Langenburg talk about their week in Orlando at the 2025 IAI Educational Conference. Hear about Quality Metrics, limited examinations, and linking cases together, and hear from some of the conference attendees.
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Episode 286 - Forensic Science Ireland Interview
Sep 3001:42:52Tap to summarizeIn this episode Eric poses to Glenn a Mandela effect question concerning household cleaning products. After that, the guys celebrate the 4th of July holiday by welcoming their guests from Ireland. Four fingerprint examiners from Forensic Science Ireland (FSI), the national forensic lab in Ireland, join the podcast. The guests are Dr. Aoife Power, Dr. Craig Mullen, Mr. Columb Doherty, and Dr. Kim Connick. Glenn and the guests talk about their time at the recent European Academy of Forensic Science (EAFS) conference in Dublin in May 2025. The examiners from FSI discuss their research, posters, and presentations from EAFS. Eric is also curious about their new AFIS system and has lots of questions about their processes. The guests discuss forensic fingerprint practices in Ireland and especially working in their new national laboratory. Forensic Science Ireland: https://forensicscience.ie/ Dr. Kim Connick: kconnick@fsi.gov.ie
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Episode 285 - Michael Whyte Interview - Latent to Latent Comparisons
Aug 1201:08:18Tap to summarizeIn this episode, the guys start with a product-based Mandela effect question. Then they welcome back long-time friend of the show and webmaster, Michael Whyte from the New South Wales police force in Australia. Michael has a question for Glenn and Eric, regarding latent-to-latent comparisons, using latent prints as 'proxy exemplars' when the exemplars are worse than the latent prints or incomplete, and various off-shoots of these questions. The guys discuss the theoretical basis and some of the legal issues that arise in both the U.S. and Australia.
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Episode 284 - Black Box '22 - Part 2 (with Brendan Max)
Jul 2801:28:36Tap to summarizeIn this episode, Eric stumps Glenn with a geography based Mandela Effect question. Then the guys welcome their guest commentator, Brendan Max, Public Defender and Chief of the Forensic Science Division in Chicago, Illinois. Eric, Glenn, and Brendan take a second look at the 2025 FBI/Noblis follow-up black box study for latent fingerprints. The guys had previously done a cursory review of the paper in Episode 282, and now wanted to dig in a bit into the appendices and take another look at some trends. Brendan offers his insights and shows that he’s pretty proficient with a spreadsheet too! The guys go back and forth discussing the strengths and limitations of the study and where the methodology and practice has likely improved since the original Black Box study (conducted in 2009). Article is available for free at: doi.org/10.1016/j.forsciint.2025.112457
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Episode 283 - DNA & Patterns
May 26, 202501:09:34Tap to summarizeGlenn Langenburg and Eric Ray review two articles from Cell that focus on the genetic basis for ridge development and pattern formation. 'The developmental basis of fingerprint pattern formation and variation' by Glover, et al., and 'Limb development genes underlie variation in human fingerprint patterns' by Li, et al. Our understanding of these complex processes continues to grow, and these papers further support our field and our conclusions.
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Episode 282 - Noblis-FBI Black Box 2 Fingerprint Study
May 10, 202501:22:36Tap to summarizeIn this episode, Glenn and Eric start with a quick game of “A Truth, A Lie, and a Mandella Effect”. Then they pose a question from a listener regarding interest in a forum where listeners can go and discuss the episodes of the show, ask questions, and chat “amongst themselves”. Finally they get to the long awaited Noblis/FBI study “Black Box 2” latent fingerprint error rate study. This is a re-do of the 2011 black box study for latent fingerprint performance. This study “Accuracy and reproducibility of latent print decisions on comparisons from searches of an automated fingerprint identification system” by Hicklin, Richetelli, Taylor and Buscaglia (For Sci Intl, 370 (2025), 112457), reported the performance of 156 U.S. latent print examiner participants each reviewing about 100 latent prints/comparisons resulting in over 14,000 trials. The study reports numerous statistics of performance such as sensitivity (63%), specificity (70%), false positive error rate (0.2%), and false negative error rate (4.2%). The guys also discuss some important study design differences, plus there are a lot of data in the appendices. Finally they talk about the number of false positives made in the study (n=23) and the fact that 13 of those 23 were made by one participant and how that impacted the results. Article is available for free at: https://doi.org/10.1016/j.forsciint.2025.112457
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