Shows
Double Loop PodcastEpisode 283 - DNA & PatternsGlenn 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.2025-05-261h 09
Double Loop PodcastEpisode 281 Kasey Wertheim TributeEric Ray and Glenn Langenburg pay tribute to our colleague and friend. Kasey Wertheim passed away on March 7, 2025 and will be greatly missed. Please join us as we remember his legacy and contributions to the field of fingerprints and tell a few personal stories.2025-04-061h 01
Double Loop PodcastEpisode 280 - Pat Wertheim TributeEric Ray and Glenn Langenburg pay tribute to our mentor and friend. Pat Wertheim recently passed and will be greatly missed. Please join us as we remember his legacy and tell a few stories.2025-03-211h 17
Double Loop PodcastEpisode 278 - Aussie Paper on Examiner DisagreementsIn this first recorded episode of 2025, Eric and Glenn start with Eric being pedantic in his “A Truth, A Lie, and a Mandela Effect”. The guys catch up on New Year stuff and then launch into a review of a research paper from New South Wales, Australia, titled “How often do fingerprint examiners disagree in routine casework?” by O’Connor and Chapman (2024) from Forensic Science International. Eric first discusses some of the important differences in casework workflow and conclusions between Aussie examiners and U.S. examiners. Then they discuss the results of the paper and the significance of the findings. At the end...2025-03-031h 02
Double Loop PodcastEpisode 276 - History Episode - Stories of the ForefathersIn this episode the guys discuss historical figures in the field of fingerprints. At the top of the episode Eric gives Glenn an Australian themed “A Truth, a Lie, and a Mandela Effect”. Glenn tells a couple of stories from his trip to London, which also inspired the topic for the episode. Because of Glenn’s time in Switzerland this fall reading old texts, he learned a lot about the early days of fingerprints. The guys discuss contributions, stories and cases from Juan Vucetich, Sir Francis Galton, Sir Henry Faulds, Sir Edward Henry, Alphonse Bertillon, Dr. Edmond Locard, and more!2024-12-091h 34
Double Loop PodcastEpisode 275 - 2024 IAI Conference: The Reno RecapThe guys start out with a quick explanation of why Glenn’s sound is so bad (he’s in Switzerland recording). They also start the new “season”, post-IAI with a new game: "Truth, Lie, or Mandela Effect?" Eric talks about his fall conference junket and then the guys finally catch up on the IAI. They discuss their favorite lectures, workshops, and activities at the 2024 IAI Conference in Reno, NV. They summarize some of their standout lectures that they attended. Glenn then discusses how the Double Loop Podcast vendor booth went with Rebecca Coutant running it during the conference. Rebecca also was “Our...2024-11-011h 21
Double Loop PodcastEpisode 272 - DNA and Human Factors Expert Working Group ReportThis super-sized episode has the guys interviewing several people from a recent Expert Working Group on Human Factors in the discipline of DNA. Glenn starts by giving Eric his “Where in the Whorld” question and they catch up on some recent travels. Glenn also explains why this episode does NOT feature a continuation of the previous episode on the Peacemaker case, but instead pivots to a different DNA topic. In May 2024, NIJ/NIST released a Human Factors and Forensic DNA Interpretation report. (The) Niki Osborne, Ph.D., the project lead and contractor for NIST (Natl Institute of Standards and Technology) desc...2024-06-301h 41
Double Loop PodcastEpisode 271 - SD v Peacemaker Case and Anjali Ranadive InterviewEric and Glenn start the episode with a Where in the Whorld that leads to a little catching up. Glenn was in NYC recently (saw the Harry Potter show on Broadway, indulging his “magician” side) and Eric has been doing the conference circuit. Eric is also soliciting fingerprint experts for a research project on ‘estimating image resolution’ based on ridge density. The guys also got a listener voicemail that they discuss (and roundly disagree with). Finally they discuss the main topic for the show, a homicide case and trial that Glenn testified in: South Dakota v. Jeremiah Peacemaker. Glenn covers his invo...2024-05-061h 26
Double Loop PodcastEpisode 268 - Steve Johnson InterviewEric Ray and Glenn Langenburg sit down for a chat with Steve Johnson about face examiners, face comparisons, and the IAI. Steve's background includes latent prints, forensic art, face comparison, crime scene, and many positions with the IAI. He shares the future of the face discipline and how the IAI is working towards a certification process.2024-03-2149 min
Double Loop PodcastEpisode 267- Chloe George Interview - Research on Phalange PatternsEric and Glenn host another guest from Australia in today’s episode. After another round of Where in the Whorld and a few stories from Eric’s childhood, the guys welcome Chloe George from New South Wales Police Force, Australia. Glenn saw Chloe present at IAFS, where her presentation on phalange pattern classification won best Oral (Presentation). Chloe introduces a system of phalange pattern classification first described by Marie Ploetz-Radmann in 1937. She walks us through the system and the 12 general pattern types in phalanges and then also shares her personal data and testing that she performed.
A copy of her IAFS...2024-03-0952 min
Double Loop PodcastEpisode 264 - Fingerprints Proven by AI to Not Be Unique!Eric and Glenn respond to the recent allegations that a computer science undergraduate at Columbia University, using Artificial Intelligence, has “proven that fingerprints aren’t unique” or at least…that’s how the media is mischaracterizing a new published paper by Guo, et al. The guys dissect the actual publication (“Unveiling intra-person fingerprint similarity via deep contrastive learning” in Science Advances, 2024 by Gabe Guo, et al.). They state very clearly what the paper actually does show, which is a far cry from the headlines and even public dissemination originating from Columbia University and the author. The guys talk about some of the importa...2024-01-201h 26
Double Loop PodcastEpisode 263 - Caitlin Rough InterviewIn 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...2024-01-1247 min
Double Loop PodcastEpisode 261 - Fall Travel CatchupGlenn 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?)2023-12-1958 min
Double Loop PodcastEpisode 260 - Tales from the CourtroomEric 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!2023-11-251h 41
Double Loop PodcastEpisode 258 - Gap Science InterviewEric 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.2023-09-1532 min
Double Loop PodcastEpisode 257 - Which Forensic Discipline Is The Most Reliable?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...2023-08-131h 19
Double Loop PodcastEpisode 256 - Tom Busey - CSDIAIGlenn 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.2023-07-201h 58
Double Loop PodcastEpisode 255 - Busey Visual Evidence PaperEric 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.2023-06-1251 min
Double Loop PodcastEpisode 254 - NIST Latent AccuracyGlenn 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/2023-04-0354 min
Double Loop PodcastEpisode 253 - Bigger Blacker BoxesEric 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.2023-02-211h 08
Double Loop PodcastEpisode 252 - Alan McNamara InterviewGlenn 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.2023-02-081h 28
Double Loop PodcastEpisode 251 - Alan McNamara Case - Part 2Eric 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...2023-01-141h 19
Double Loop PodcastEpisode 250 - Alan McNamara Case - Part 1Glenn 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.2023-01-061h 08
Double Loop PodcastEpisode 247 - Brianne Breedlove InterviewGlenn 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.2022-06-291h 19
Double Loop PodcastEpisode 246 - Stephan Cowans CaseToday, 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...2022-05-071h 34
Double Loop PodcastEpisode 245 - Errors and CVs and DisclosureEric 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.2022-03-311h 10
Double Loop PodcastEpisode 243 - New Years Grab BagEric Ray and Glenn Langenburg catch up on a mix bag of topics in the first episode of 2022. Emails on the new conclusion proposal, setups for photography with transmitted light, and the main topic on "qualitative statements". ANAB accreditation requires agencies to include a statistic or a qualitative statement when reporting an association. What does that mean? What qualifies as quantitative? Is this a new thing? Thanks for listening for another year!2022-01-311h 00
Double Loop PodcastEpisode 241 - Blind Proficiency Testing PaperEric Ray and Glenn Langenburg discuss the recent paper on Blind Proficiency Testing from the Houston Forensic Science Center: "Latent print quality in blind proficiency testing: Using quality metrics to examine laboratory performance" by Brett O. Gardner, Maddisen Neuman, and Sharon Kelley. The paper describes the results of over two years of blind proficiency testing in the latent print unit. No false positive errors were detected over all samples when the examiners were not aware that they were being tested. The paper also describes the use of LQMetric in measuring the Quality of the sample latent prints. A fantastic paper...2021-12-0155 min
Double Loop PodcastEpisode 238 - Dror and Scurich ArticleGlenn Langenburg and Eric Ray review the 2020 article from Itiel Dror and Nicholas Scurich. "(Mis)use of scientific measurements in forensic science" was published in Forensic Science International: Synergy. The article criticizes published accuracy studies in the latent print and firearms disciplines and suggests an alternative method for handling inconclusive decisions and calculating an error rate for the field. The episode details factual errors in almost every part of the article and suggests the real motivation behind these arguments. But first Eric and Glenn read some emails and catch up on our return to conferences.2021-07-061h 16
Double Loop PodcastEpisode 237 - Testifying After an ErrorGlenn Langenburg and Eric Ray discuss how to testify in court after an error occurs. Examiners nervous about upcoming testimony can find tips whether you made the error or a co-worker made an error and whether it was an erroneous identification or an erroneous exclusion. The court and juries do not expect us to be perfect, and we should claim to be. It's important to be able to discuss the Quality Assurance protocols that our labs have in place.
Watch Eric and Glenn compare fingerprints here - https://youtu.be/C5KmM6cAKpk
And join us for Wed Happy Hour...2021-04-261h 13
Double Loop PodcastEpisode 235 - Todd Weller InterviewGlenn Langenburg and Eric Ray are joined by Todd Weller to discuss the firearms/toolmarks discipline. Todd was involved in the NY firearms case from Episode 227 and shares his experiences there. The guys then talk through accuracy studies for firearms examiners and similarities and differences between firearms and fingerprints. Lots to cover in an extra-long episode.2021-03-121h 37
Double Loop PodcastEpisode 233 - GYRO Accuracy PaperGlenn Langenburg and Eric Ray finally get back on track with a review of a recent article on GYRO markings. "Evaluating the Accuracy and Weight of Confidence in Examiner Minutiae Annotations" was written by Jeremy John and Henry Swofford and published in the JFI. The study measured whether examiners placed minutiae markers on true minutiae using Green, Yellow, and Red markers. It then compared the color choices of examiners against the color choices of the automatic LQMetric and DFIQI algorithms. Eric and Glenn will soon be publishing videos of themselves conducting comparisons, using GYRO, and discussing their similarities and differences...2021-02-161h 09
Double Loop PodcastEpisode 232 - Differing Conclusions ArticleGlenn Langenburg and Eric Ray review the newest article from Austin Hicklin, Bradford Ulery, Madeline Ausdemore, and JoAnn Buscaglia. Why do latent fingerprint examiners differ in their conclusions? reviews data from the Black Box, White Box, and Eye Tracking papers, summarizes trends through all of that research, and recommends changes for the fingerprint field.2021-01-061h 29
Double Loop PodcastEpisode 229 - Bob GarrettGlenn Langenburg and Eric Ray pay special tribute this week to a giant in the fingerprint world, Bob Garrett. With the passing of Bob and a few other close friends and colleagues, Glenn and Eric want to look back at the contributions of Bob Garrett in particular. In his single year as president of the IAI, he was instrumental in responding to the NAS Report, addressing the McKie controversy, and moving forward the Standardization II Committee. Please join us in remembering Bob and all of the other friends and colleagues that we've recently lost.2020-10-131h 22
Double Loop PodcastEpisode 227 - NY Firearms CaseGlenn Langenburg and Eric Ray review a recent court decision on firearms testimony. NY v Ross was a recent Frye case where the testimony of firearms examiners was restricted to only class characteristics. Was this a fair decision? Did the judge raise good points? How does this case relate to latent print testimony and latent print accuracy studies? Join us for an hour of fun talk as we dive deep into the nerdy intersection of science and law.
https://legalaidnyc.org/wp-content/uploads/2020/07/Ross-Frye-Decision_Full-.pdf2020-09-021h 20
Double Loop PodcastEpisode 226 - Best Latent Print BooksGlenn Langenburg and Eric Ray were recently asked which latent print books they recommend the most. This episode they talk through the absolute creme de la creme of fingerprint tomes. New books, old books, green books, blue books. Whether you're developing or comparing ridges, we've got a list of what you need to read. Also make sure to join us Wed nights at 8pm EDT for Virtual Happy Hour at https://discord.gg/b39pp6j2020-07-201h 01
Double Loop PodcastEpisode 224 - Forensics in the New NormalGlenn Langenburg and Eric Ray take a break from normal interviews and research reviews to host a laid-back happy hour discussion on how things have been different in the past few months in forensic crime labs. Carey Hall, Becca Coutant, and Josh Connelly join our discussion that meanders from discussions on web-based training, remote testimony, recent changes to in lab life, and TV recommendations. Our Discord server is at https://discord.gg/b39pp6j. Happy Hour is Wed's at 8pm EDT.2020-06-161h 13
Double Loop PodcastEpisode 222 - How to Fix a Drug Scandal Documentary - Part 2Eric and Glenn finish out their discussion of the new Netflix documentary “How to Fix a Drug Scandal” (2020). In this episode we switch our focus on the dry-labbing of drug tests by Annie Dookhan, and how long it took for those tests and convictions from those test to finally get tossed. The episode concludes with the story of Luke Ryan and his crusade to finally find the evidence that clearly demonstrated that Sonja Farak had been using drugs for years and not just months.
Join Glenn and Eric on Discord for virtual Latent Print Examiner Happy Hour, Wednesdays 8-10PM EST...2020-05-061h 15
Double Loop PodcastEpisode 219 - David Camm Case - Part 2The case against David Camm is about to be turned on its head. Eric Ray and Glenn Langenburg continue the story with a second and third trial and the introduction of a mountain of evidence against a new suspect. The episode concludes with an in-depth discussion on the importance of considering multiple scenarios in bloodstain pattern and all forensic disciplines. It all ties back to our previous discussions of activity level propositions.2020-04-151h 11
Double Loop PodcastEpisode 216 - OSAC Update and Travel StoriesGlenn Langenburg returns from international travels (just in time) and brings stories from distant lands of England and Minnesota. As the discussion turns to conclusions, Eric Ray brings an update from the OSAC Friction Ridge Subcommittee. Check the NIST OSAC website in the near future for updated versions of Friction Ridge Subcommittee proposed standards.2020-03-191h 06
Double Loop PodcastEpisode 214 - Simon Bunter InterviewGlenn Langenburg is joined by Simon Bunter from Keith Borer Consultants to discuss a number of cases where activity level propositions were key factors. Can a print survive after the surface is cleaned? What if the surface is painted over? Simon tells some amazing stories that should make every latent print examiner question the timeline of when a latent print was left on a surface.2020-02-241h 11
Double Loop PodcastEpisode 213 - Anouk de Ronde InterviewEric Ray and Glenn Langenburg are joined by Anouk de Ronde from the Amsterdam University of Applied Sciences to continue the discussion on activity level propositions. Anouk has published on how to construct a logical framework for considering all the information in a latent print to assist in establishing probabilities for competing hypotheses. Did he climb the railing or just lean against it? Was the pillowcase changed or was the pillow pressed down? Just like you wouldn't reach an Identification without looking at each individual minutiae, this framework allows for examination of each data point before making a conclusion on...2020-02-041h 05
Double Loop PodcastEpisode 212 - Activity LevelIn this episode Glenn and Eric dig into ‘activity level propositions’, which will start a series of episodes that takes a deep dive into this topic. We lay the groundwork for the topic by discussing fundamental forensic science papers, such as Evett, et al. “The impact of the principles of evidence interpretation on the structure and content of statements” (Science & Justice, 2000) and other works by Cook and Jackson. We highlight the need for formal declaration of propositions regarding ‘source’, ‘activity’, and ‘crime (offense)’ levels. Lastly, we discuss aging (time since deposition) of latent prints and the dangers of these statements based on a visual ex...2020-01-151h 05
Double Loop PodcastEpisode 211 - OSAC & ASB UpdateEric Ray and Glenn Langenburg get passionate about policies. Stirred up about standards. PO'd about SDO's. After a quick refresher on how NIST, OSAC, AAFS, and ASB fit together in the Standards Development process, Eric and Glenn give an update on the draft standards for latent prints. Where are the standards that we've been waiting for? There was a recent meeting the Friction Ridge group with ASB, and things did not go well for those of us that would like to see the process move forward. While you're waiting for things to move forward, don't forget to check out the...2020-01-081h 17
Double Loop PodcastEpisode 210 - Brendan Max InterviewIn this episode, Glenn and Eric interview Brendan Max, Chief of the Cook County Public Defender Forensic Science Unit in Illinois. They discuss his new article “Assessing Latent Print Proficiency Tests: Lofty Aims, Straightforward Samples, and the Implications of Non-Expert Performance” (Max, Cavise, and Gutierrez in JFI 2019;69(3)). Brendan shares his views on proficiency tests: are they meaningful? What about verifications in proficiency testing? What does it mean to ‘fail’ a test? How do lawyers and judges view proficiency tests? He describes his basic strategy for litigating forensic evidence and explains why the research in the field of latent prints is so criti...2019-12-151h 16
Double Loop PodcastEpisode 209 - Friction Ridge Process MapEric Ray and Glenn Langenburg talk through the latest document out of the OSAC Friction Ridge Subcommttee. Last month they released an updated, and detailed, process map for friction ridge examinations. Follow along by downloading the pdf from the OSAC FRS website, https://www.nist.gov/topics/forensic-science/friction-ridge-subcommittee.
Eric and Glenn are also happy to announce the Double Loop Podcast merch store. Go to doublelooppodcast.com, click on the Store tab, and help support the show.2019-12-091h 07
Double Loop PodcastEpisode 207 - AC Brogdon InterviewEric Ray starts the show sharing some big news with Glenn Langenburg and the listeners. The guys are then joined by AC Brogdon, president of the California State Division of the IAI for an discussion on the importance of the work that we do. AC shares some stories of his early life, and how those experiences shaped the person that he is and how that continues to inspire and motivate him. It's vitally important for examiners and investigators to remember the victims as they do their work and that it's not just another day at the office for those directly...2019-11-1657 min
Double Loop PodcastEpisode 205 - PNW Conference PanelGlenn Langenburg leads a panel discussion (with Eric Ray joining via phone) at the Pacific Northwest Division of the IAI / Northwest Association of Forensic Scientists Joint Conference with guests and Janis Puracal from the Forensic Justice Project and Carey Hall. The panel discussion explores the Janis's history with exonerations, innocence, justice reform, and forensic science and the challenges that face those that have been erroneously convicted. The conversation also explores the challenges that forensic scientists face in these areas and steps that they can take to ensure neutrality and that justice is served.
Head to DoubleLoopPodcast.com for more episodes...2019-10-171h 26
Double Loop PodcastEpisode 204 - 2019 IAI ConferenceJoin Glenn Langenburg and Eric Ray in Reno, NV for the 2019 International Association for Identification conference. We are joined by Becca Coutant, Carey Hall, Nicole Praska, Claudine Carter Pereira, and Jason Jardine and cover a number of topics including limited examinations, defense attorney perspectives, conclusion terminology, blood prints, management, and stats. There's even a little story of Glenn losing his cool and an out-take for the blooper reel. The conference was fantastic, and big thanks to all of the new listeners that we met during the week.
To celebrate 200+ episodes, an old photo of Glenn with John Vanderkolk is included.2019-09-2347 min
Double Loop PodcastEpisode 203 - FBI Persistency PaperEric Ray and Glenn Langenburg review a new paper that's been long in the making. "The permanence of friction ridge skin and persistence of friction ridge skin and impressions: A comprehensive review and new results" by Monson, et al. was recently published in Forensic Science International. The paper details the persistence and permanence of 1st, 2nd, and 3rd level detail over multiple years. There are important takeaways from the paper although it isn't quite the level of the FBI/Noblis papers. So let's see what the guys think.2019-09-161h 07
Double Loop PodcastEpisode 202 - Idaho InterviewsEric Ray was recently teaching in Idaho (the ID state) and had the opportunity to sit down with Nick Craven, Katlyn Shelar, Whitney Betzel, and Tara Koho and talk with them about topics ranging from latent print exclusions, AFIS candidate lists, and the future of statistical models. Glenn Langenburg then joins Eric to continue the discussion with some follow-up points and continuing the conversation further into Exclusion policies and requirements, the nature of risk, and a preview on how to use a 5 Conclusion scale.2019-08-211h 33
Double Loop PodcastEpisode 201 - Gaze Detection ArticleEric Ray and Glenn Langenburg discuss the new article from Austin Hicklin, Brad Ulery, Tom Busey, and company researching latent print examiners with eye tracking equipment. Gaze behavior and cognitive states during fingerprint target group localization was published in Cognitive Research and examines what we look at and how context plays a huge part in this process. Download the paper online and follow along as we explore a great new paper.2019-07-251h 07
Double Loop PodcastEpisode 200 - Michael Whyte InterviewEPISODE 200!!! - Eric Ray and Glenn Langenburg celebrate the big number 200 with an overseas interview with Australian latent print examiner and friend of the show, Michael Whyte. The guys talk forensics down under, some of the travels, teaching, and technology that Michael is involved with and announce DoubleLoopPodcast.com. Check it out, and let us know how we can make it even better.2019-07-111h 11
Double Loop PodcastEpisode 198 - Archie Williams CaseEric Ray and Glenn Langenburg start the show talking about some exciting new classes that they have developed. Then they discuss which is more correct: 2009 "NRC" Report or "NAS" Report. Finally, they describe the available facts in the recent Archie Williams Innocence Project exoneration case. He was freed after 36 years in prison for rape based on eyewitness identifications, but an AFIS hit now implicates another person.2019-04-011h 01
Double Loop PodcastEpisode 197 - Review of Miami-Dade Error RatesGlenn and Eric start with a brief chat about ethics and the recent JFI letter regarding testing and studies involving human subjects. They then jump into the main discussion on the "Review of Several False Positive Error Rate Estimates for Latent Fingerprint Examination Proposed Based on the 2014 Maimi-Dade Police Department Study" by Madeline Ausdemore, Jessie Hendricks, and Cedric Neumann. The review found that the data best fit a model of two error rates: one for when the true match is not present and one where the true match is one of the individuals presented. The article concludes with follow-up letters...2019-03-181h 14
Double Loop PodcastEpisode 196 - Gianni Ribeiro Article and InterviewEric Ray and Glenn Langenburg discuss post-Laura Interview thoughts after last episode's "lay person" interview. They tie in a new paper surveying mock-jurors, published by Gianni Ribeiro from Australia. Later, Gianni calls in from Oz to discuss her research. Oh, and Eric and Glenn both come up with genius ideas this episode.2019-03-071h 28
Double Loop PodcastEpisode 195 - Laura Keck InterviewGlenn Langenburg and Eric Ray interview friend-of-the-show, Laura Keck, and dive deep into how forensic evidence is interpreted by a lay person. Does one fingerprint identification vs. 13 fingerprint identifications make a difference? What if the prints were on an inner drug baggie vs. an outer drug baggie? What is an acceptable error rate for latent prints or DNA? What if there is no other forensic evidence? Laura's perspective as a lay person (but with knowledge and interest in forensic science) and what she expects from expert testimony should lead to experts taking a close look at how they testify, what...2019-02-221h 13
Double Loop PodcastEpisode 194 - Melting Pot of TopicsEric Ray shares some big news and then shares a story about the dictionary. Glenn Langenburg brings another Super Fan into the fold as the Double Loop Podcast website starts to come together and some new research from Australia ( https://www.youtube.com/watch?v=7dG6Rw8_KLg ). They both then revisit the discussion on investigative leads. It's important to understand the distinction between reporting AFIS hits as preliminary without verification and a true "investigative lead" where there are only limited features in agreement. This episdoe is sponsored by Go Evidence Laboratories.2019-02-1451 min
Double Loop PodcastEpisode 192 - Mark Stolorow InterviewGlenn Langenburg and Eric Ray are proud to be joined by Mark Stolorow. Before his years guiding the creation of the OSAC and his days with NIST, he had a varied history getting kicked out of the chemistry department, avoiding the draft, working as a cop, researching blood typing, and wearing plaid jackets. Listen to the interview for all the details of a fantastic career. This episode is sponsored by GO EVIDENCE LABORATORIES.2019-01-221h 13
Double Loop PodcastEpisode 191 - Christophe Champod InterviewEric Ray and Glenn Langenburg are joined for another episode discussing statistics and probabilities by Professor Christophe Champod from the University of Lausanne. Christophe takes us on a history of his work on fingerprint statistics, his past, current, and future research projects, his hope for the future of statistics in fingerprint comparisons, and how the newest Swiss model is available for use through the Pianos software. This episode is sponsored by GO EVIDENCE.2019-01-131h 31
Double Loop PodcastEpisode 190 - Gianni Ribeiro Interview (and OSAC)Eric Ray and Glenn Langenburg interview Australian researcher Gianni Ribeiro at the December 2018 OSAC meeting in Phoenix, AZ. Gianni tells the guys about her research interests studying how juries weigh evidence vs. alibis and other jury studies. She also talks about her impressions of the experts gathered at the OSAC meeting, the discussions going on related to likelihood ratios, and the battles over issues big and small in various subcommittees. This episode is sponsored by GO EVIDENCE LABORATORIES and is sponsored by IDEMIA.2018-12-3056 min
Double Loop PodcastEpisode 189 - Henry Swofford InterviewGlenn Langenburg and Eric Ray are joined in-person by Henry Swofford as they discuss his career with the Army Crime Lab and the development of FRStat, a model that produces a similarity score between two compared fingerprints and a ratio of how that score fits into same source or different source distributions. The guys discuss why the model was developed, how it's being used, and some of the models limitations. This episode is sponsed by GoEvidence Forensic Laboratories, and this episode is also sponsored by IDEMIA.2018-12-221h 19
Double Loop PodcastEpisode 188 - Cedric Neumann InterviewGlenn Langenburg and Eric Ray are joined by Cedric Neumann to discuss all things statistical models, probabilities, likelihood ratios, Bayes factors, and more. Cedric discusses his history of research, his history in forensics, and how that's brought him from Switzerland to the UK to the US. This episode is sponsored by IDEMIA and their new Case AFIS product.2018-12-101h 15
Double Loop PodcastEpisode 187 - Richard RamirezEric Ray and Glenn Langenburg move into a discussion of a new case with the help of special guest Becki Daher. Richard Ramirez, the Night Stalker, terrorized California in the mid-1980's before he has caught with the help of fingerprints and new AFIS technology. Becki Daher was working for the Orange County Sheriff's Office at the time and lifted the fingerprint from the car window that eventually led to his arrest. Join us in a discussion of Ramirez's crimes, the terror felt by the residents of California, and the high-tech and low-tech techniques that led to his arrest and...2018-12-031h 20
Double Loop PodcastEpisode 186 - Making a Murderer - S2 - Part 4Eric Ray and Glenn Langenburg wrap up the final episode in their series on Making a Murderer Season 2 with all of the craziness that didn't fit in all the previous episodes. Doesn't the bloodstain shape mean that he's innocent? Or mean that he's guilty? What about the lack of fingerprints? The burn barrel? The carpet cleaner? The bullet wax? Is Teresa even dead? Is the Double Loop Podcast just another part of the grand conspiracy by the government against Steven Avery? The answer to almost all of those questions is "no", but listen anyway as we close out this case...2018-11-271h 33
Double Loop PodcastEpisode 185 - Making a Murderer - S2 - Part 3Eric Ray and Glenn Langenburg start to wrap up this second season of Making a Murderer with a discussion of the other new suspects in the case, a bit of internet drama, and the vast Wisconsin conspiracy. They then finally move into the discussion of Brendan Dassey and his ongoing appeals process, and how difficult it is for federal courts to review state court decisions. (This episode is sponsored by IDEMIA.)2018-11-151h 04
Double Loop PodcastEpisode 184 - Making a Murderer - S2 - Part 2Glenn Langenburg and Eric Ray spend this episode talking about even more of the forensic evidence from the second season of Making a Murderer. They start with a review of the DNA evidence from the hood latch and the bullet fragment. Can there be too much DNA? They also discuss the trace analysis of the bullet fragment, the lack of fingerprints, the mysteries of brain fingerprinting, and even more of the evidence in the Steven Avery case. (This episode is sponsored by IDEMIA.)2018-11-081h 10
Double Loop PodcastEpisode 183 - Making a Murderer S2 - Part 1Glenn Langenburg and Eric Ray delve into the second season of Making a Murderer. They start by reviewing the evidence that they had discussed from the first season and then discuss their impressions of the new characters in the docu-series. They then move into a detailed discussion of the experiments conducted by Kathleen Zellner and her new forensic experts on behalf of Steven Avery. The blood and bloodstain patterns are covered. (This episode is sponsored by IDEMIA.)2018-11-021h 20
Double Loop PodcastEpisode 182 - Tucson Prime Time RapistGlenn Langenburg and Eric Ray are joined by John Swartz, retired from the Tucson Police Department, for a discussion on the Prime Time Rapist case from the mid-1980's. John talks about how the series of 30 attacks on 90 people affected the Tucson community and the department investigating the crimes. Before the perpetrator could be caught, there was a fingerprint examination error that led to other mistakes and civil rights violations. After discussing the details of the case, Glenn and Eric ask John about how the error affected the examiner, the latent print unit, and how the unit was treated by...2018-10-231h 06
Double Loop PodcastEpisode 181 - Fingerprint AnalogiesEric Ray and Glenn Langenburg begin the episode with a discussion of an article from a law journal by Barbara Spellman titled, Communicating Forensic Evidence: Lessons from Psychological Science. Among her main points are that statistics, likelihood rations, and random match probabilities are terrible ways of communicating information to juries. She goes on to say that there are a number of misconceptions in latent fingerprint comparisons that must be addressed to juries and that analogies might be a better way to convey information to them. While Glenn and Eric agree and disagree with some of those points, they conclude the...2018-10-161h 04
Double Loop PodcastEpisode 180 - IAI Recertification TestGlenn Langenburg and Eric Ray report on a heated and controversial topic that caught the attention of the latent print world in the summer of 2018, the re-designed IAI Re-Certification test. Every five years, Certified Latent Print Examiners must take a comparison test. The old one was notoriously easy, but that has recently changed, and the error rate was higher than some expected. Carl Speckels raised the topic on the CLPEX.com message board and it was discussed at length at the 2018 IAI Conference. The topic is discussed even further here with some suggestions on how to improve the test while...2018-10-091h 28
Double Loop PodcastEpisode 179 - IDEMIA Case AFISGlenn Langenburg and Eric Ray interview Teresa Wu from IDEMIA about the new product launch of IDEMIA's Case AFIS. The new system can quickly scan in exemplar prints from any type of standard or non-standard cards which then serve as a mini-database for an AFIS search. Efficiency is vastly improved when the computer takes care of the searching aspect of latent print comparisons. This process can also almost eliminate erroneous exclusions from casework. (This episode is sponsored by IDEMIA.)2018-09-2954 min
Double Loop PodcastEpisode 178 - The Staircase - Part 4Glenn Langenburg and Eric Ray try to wrap up any final discussion points from The Staircase docu-series. After Michael Peterson's conviction was overturned and a new trial was ordered, new attorneys come in, but an Alford plea is reached and Michael Peterson is released. Should a retrial have gone forward? What decisions did the original judge regret? What mistakes did the prosecution make? What is a blowpoke? And could an owl have been the murderer and/or the murder weapon? (This episode is sponsored by IDEMIA.)2018-09-2439 min
Double Loop PodcastEpisode 177 - The Staircase - Bart Epstein InterviewGlenn Langenburg and Eric Ray are graciously joined by Bart Epstein in an interview about bloodstain and other forensic evidence from the trial of Michael Peterson in the death of Kathleen Peterson. Bart Epstein explains his involvement in the case, his opinions on the blood evidence, and where he agreed and disagreed with Duane Deaver and Dr. Henry Lee. This episode is also sponsored by IDEMIA and their new product, Case AFIS.2018-09-131h 24
Double Loop PodcastEpisode 176 - The Staircase - Part 2In our second dive down The Staircase, Eric Ray and Glenn Langenburg start looking closely at all of the forensic evidence available in the case and what it all means. The documentary leaves lots of questions that we try to answer in this episode like: Can you trace an impact back to a point in space? Could the wall, rail, or step have caused all of the impact sites? Where was the defense medical examiner expert? Did the prosecutor have other bloodstain experts ready to testify besides Deaver? Was there castoff? Were there other wounds besides the scalp lacerations? Was...2018-09-071h 12
Double Loop PodcastEpisode 175 - The Staircase - Part 1Eric Ray and Glenn Langenburg focus their forensic science backgrounds on the infamous Kathleen Peterson murder as it was portrayed in The Staircase. The guys review their initial impressions of the case and the documentary and then tell the basic outlines of the story where Michael Peterson is suspected, arrested, charged, and convicted of the murder of his wife. There are so many twists and turns to this story that we had to get them all out of the way in this episode before focusing on the forensics in upcoming episodes.2018-09-0458 min
Double Loop PodcastEpisode 174 - 2018 IAI ConferenceGlenn Langenburg and Eric Ray return to the annual IAI conference in San Antonio to talk to attendees about the interesting lectures and workshops that they've seen this year. Morgan Hays from Florida talks about how he stays current with the field as a supervisor and how the exclusion and verification topics were covered at the conference. Do you trust your verifier? Linda Manigault from Nevada then joins the conversation and discusses the workshops on FRStat and statistical models that she attended. Glenn ends the episode with a BIG announcement!2018-08-1425 min
Double Loop PodcastEpisode 173 - AAAS Report - Final WordGlenn Langenburg and Eric Ray wrap up the three-part discussion on the AAAS Report on the Quality and Gap Analysis of Latent Fingerprint Examination. Surprisingly, the guys agree with many of the recommendations and conclusions in the document with an occasional quibble or clarification. As was hinted in the past two episodes, there are more serious concerns with the report's suggested language and proposed limitation of the word "identification".2018-08-0954 min
Double Loop PodcastEpisode 172 - AAAS Report and Carey Hall InterviewGlenn Langenburg and Eric Ray continue the discussion on the pros and cons of the AAAS report. Carey participated with the review of the report and discusses the positive recommendations and the limitations that come from the report not being published in a traditional peer-reviewed journal. After that discussion wrapped up, Carey, Eric, and Glenn get a little off-topic and talk about attending AFIS Users' Conferences. Carey and Glenn presented at the most recent Idemia conference on the benefits of the Case AFIS system. Eric talks about a local AFIS conference and user discussions on how data analysis can lead...2018-07-241h 01
Double Loop PodcastEpisode 171 - AAAS Report and John Black InterviewGlenn Langenburg and Eric Ray finally get around to discussing the report on latent fingerprint comparisons from the American Association for the Advancement of Science. John Black (from Black and White Forensics) was on the committee that wrote the report and joins the discussion on some of the merits and limitations of the paper. While many of the research recommendations are the next steps that the latent print field needs, they are also the same recommendations made by other reports. One of the report's main failures is the suggested wording for the identification decision.2018-07-2333 min
Double Loop PodcastEpisode 170 - Della Wilkinson InterviewGlenn Langenburg and Eric Ray are joined by Della Wilkinson from Canada to discuss the final resolution of the Bornyk case from British Columbia. Originally, Judge Funt (see Double Loop Podcast episdoe 10) ruled that the fingerprint evidence would not be admitted after conducting his own study of latent prints and his own comparison. The Crown appealed and a new trial began with the original examiner, the verifier, Della, and Simon Cole. This episode the Double Loop Podcast also pays tribute to Tony Cantu. He will be missed.2018-07-141h 29
Double Loop PodcastEpisode 169 - Simon Cole InterviewEric Ray sits down for an interview with Simon Cole from the University of California Irvine. Simon explains how he first became interested in forensics and in latent print comparisons in general, and then outlines the history of his criticisms of the field. Glenn Langenburg later joins Eric for a review of the interview and some of Glenn's perspectives on how Simon's criticisms and the latent print response have both evolved over time.2018-07-051h 42
Double Loop PodcastExtra Episode 01 - Dandridge ComparisonsGlenn Langenburg and Eric Ray continue their interview with Matt Marvin from Ron Smith and Associates about the erroneous identifications and eventual exoneration of Beniah Alton Dandridge. This video (available on YouTube via RayForensics.com) goes through an in-depth and technical review of the latent prints, the errors, the exclusions to Dandridge, and the eventual identifications to the victim's son (who discovered the body).2018-07-0401 min
Double Loop PodcastEpisode 168 - 2017 Florida ConferenceEric Ray hosts a live Double Loop Podcast discussion at the 2017 Florida Division IAI Conference in Panama City Beach, FL, and Glenn Langenburg joins via phone for the discussion. The audience hit Eric and Glenn with a variety of questions and the conversation swings from AFIS automation to using AFIS as a support for an identification decision. From the requirements that Florida courts put on latent print examiners to how to keep improving yourself so that you can make that jump into a career in forensics.2018-06-071h 13
Double Loop PodcastEpisode 167 - Matt Marvin InterviewEric Ray and Glenn Langenburg are joined by Matt Marvin of Ron Smith and Associates to discuss in greater detail the details of the Beniah Dandridge case. Matt discusses how he and RSA got involved in the case, the history of the Manning murder, the original investigation, the Dandridge trial, his appeals, RSA's involvement, and Dandridge's eventual release. Check back to RayForensics.com soon for a YouTube video detailing the comparisons in this case.2018-05-291h 11
Double Loop PodcastEpisode 166 - Familial DNAEric Ray and Glenn Langenburg discuss two forensic cases that have been in the news in the past few years. First, the guys talk about the recent Golden State Killer case. How did DNA testing and genealogy combine to solve these 40 year old crimes? What databases were accessed and was it ethical to do so? Secondly, Eric and Glenn discuss how accessing profiles of Y chromosomes from online sites led Idaho Falls detectives to Michael Usry, Jr. In 1996 Angie Dodge was murdered and Chris Tapp has been in prison for decades, but things get turned upside down when new technology...2018-05-241h 04
Double Loop PodcastEpisode 165 - Categorical vs. ProbabilisticGlenn Langenburg and Eric Ray tackle two articles in one fantastic episode. First, "Lay Understanding of 'Identification': How Jurors Interpret Forensic Identification Testimony" by Henry Swofford and Jessica Cino from the Journal of Forensic Identification. Secondly, the guys tackle a paper from the Journal of Forensic Sciences, "Comparing Categorical and Probabilistic Fingerprint Evidence" by Brandon Garrett, et al. The big question is: should we say "identification" or should we express the same conclusion in a probabilistic manner?2018-05-1854 min
Double Loop PodcastEpisode 164 - Alicia Wilcox Interview - Part 2Eric Ray and Glenn Langenburg continue their discussion with Alicia Wilcox on her research into how juries hear forensic testimony. This time we focus even more on questions of opposing experts, error rates, and what's the most important thing for an expert to have. A degree? Years of experience? An accredited lab?2018-05-0445 min
Double Loop PodcastEpisode 163 - Alicia Wilcox Interview - Part 1Glenn Langenburg and Eric Ray join with Dr. Alicia Wilcox from Husson University in Bangor, Maine in a discussion of her research juries and their understanding of forensic testimony. Even though forensic scientists may try to present data in precise and sometimes mathematical way, jurors tend to interpret forensic testimony according to whether the evidence fits well into the story that they have constructed of the crime.2018-04-2748 min
Double Loop PodcastEpisode 162 - Vos PCAST ArticleEric Ray and Glenn Langenburg discuss last year's article, Using the PCAST Report to Exclude, Limit, or Minimize Experts by Eric Alexander Vos published in Criminal Justice. We note the extreme bias of the article to exploit the emotions of the judge and jury instead of logic, reason, or data, and we find the serious flaws in many aspects of the paper.2018-04-1658 min
Double Loop PodcastEpisode 161 - Koehler Error Rate ArticleGlenn Langenburg and Eric Ray follow up from last week's discussion of Glenn's recent Daubert hearing with a 2016 article from Jonathan Koehler entitled, Intuitive Error Rate Estimates for the Forensic Sciences. As Glenn suspected, the findings of this article are suspiciously close to the center of the group of choices that participants were presented with. Although there are some larger themes that are interesting, the exact values of the error rate estimates from potential jurors do not match personal experience or even some of the cited prior works.2018-04-071h 00
Double Loop PodcastEpisode 160 - Daubert Challenge RecapGlenn Langenburg and Eric Ray return after another hiatus to share travel stories and then to discuss a Daubert hearing that Glenn recently testified in. Short version: having all this new research is way better than when we didn't have it.2018-03-2957 min
Double Loop PodcastEpisode 159 - Anja Einseln Interview - Part 2Glenn Langenburg and Eric Ray continue their interview with Anja Einseln regarding the merger of ASCLD-LAB and ANAB. Validation of methods and reasons for labs to choose accreditation are some of the many topics covered this time around.2017-12-0646 min
Double Loop PodcastEpisode 158 - Anja Einseln Interview - Part 1Glenn Langenburg and Eric Ray first revisit a couple of additional aspects of our previous discussion on defense interviews in Illinois before diving into the deep end of accreditation. Anja Einseln joins the Double Loop Podcast as our guest expert on ASCLD/LAB, ANAB, and all things accreditation. In the first half we talk about some of the changes that will be coming with the recent merger of ASCLD/LAB and ANAB and what it means for latent print units in accredited labs.2017-11-131h 08
Double Loop PodcastEpisode 153 - Austin InterviewsEric sits down with Amanda, Harres, Vanessa, Jack, and Judith from the Austin Exclusionology class to talk about latent print topics and to ask questions back at the Double Loop Podcast. Glenn later joins Eric in commenting on how the discussion went and to give his own comments on conclusion language, GYRO, and how juries interpret our results.2017-08-271h 03
Double Loop PodcastEpisode 151 - Theresa Stotesbury InterviewGlenn Langenburg and Eric Ray follow some good advice from Niki Osborne and interview Dr. Theresa Stotesbury from Trent University in Ontario. Theresa has developed a synthetic blood substitute using sol-gel for use in bloodstain pattern analysis training. We learned a lot and can't wait to find out more.2017-06-0653 min
Double Loop PodcastEpisode 139 - PCAST ReportEric Ray and Glenn Langenburg catch up after an extended hiatus and then review the recent PCAST report. The President's Council of Advisors on Science and Technology issued a scathing report calling for the end of many forensic disciplines. The Double Loop Podcast responds.2016-12-281h 01
Double Loop PodcastEpisode 134 - OJ Simpson - Part 2Glenn Langenburg and Eric Ray finish their discussion of the OJ Simpson trial, the FX OJ dramatization, and the OJ 30 for 30. Mark Fuhrman, Lance Ito, Dennis Fung and all the rest, and how the climate in LA at that time directly led to the verdict.2016-08-181h 06
Double Loop PodcastEpisode 04 - Who the Hell Are Glenn and Eric - Part 2Eric interviews Glenn about how he got started in latent prints and his favorite time teaching. The guys then discuss regional differences in the latent print field including terms, definitions, and powder color.2013-09-1742 min
Double Loop PodcastEpisode 03 - Who the Hell are Glenn and Eric - Part 1Glenn and Eric discuss the McCluskey case out of New Mexico involving testimony on identification to the exclusion of all others, an article on how forensic labs are paid per conviction from the Huffington Post, and Glenn interviews Eric in Part 1 of "Who the Hell are Glenn and Eric?"2013-09-1033 min