Glenn 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?"

Episode 03 - Who the Hell are Glenn and Eric - Part 1

Eric 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.

Episode 04 - Who the Hell Are Glenn and Eric - Part 2

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.

Double Loop Podcast

Episode 246 - Stephan Cowans Case

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.

Episode 250 - Alan McNamara Case - Part 1

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/

Episode 254 - NIST Latent Accuracy

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 about the accuracy of these different forensic techniques.

Episode 257 - Which Forensic Discipline Is The Most Reliable?

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.

Episode 259 - The 2023 IAI Conference

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!

Episode 260 - Tales from the Courtroom

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 Gibson, A.P., The Powders Process, Study 2: Evaluation of Fingerprint Powders on Smooth Surfaces, in Fingerprint Development and Imaging Newsletter. 2006.

UNIL Scale
Becue, A., Moret, S., Champod, C., and Margot, P., Use of quantum dots in aqueous solution to detect blood fingermarks on non-porous surfaces. Forensic Science International, 2009. 191: p. 36-41.

UC Scale
McLaren, C., Lennard, C., and Stoilovic, M., Methylamine Pretreatment of Dry Latent Fingermarks on Polyethylene for Enhanced Detection by Cyanoacrylate Fuming. Journal of Forensic Identification, 2010. 60: p. 199-222.

IFRG Guidelines
International Fingerprint Research Group, Guidelines for the assessment of fingermark detection techniques. Journal of Forensic Identification, 2014. 64: p. 174-197.

Hockey, D; Dove, A; Kent, T.  Guideline for the use and statistical analysis of the Home Office fingermark grading scheme for comparing fingermark development techniques.  For Sci Intl 318 (2021) 110604.

Hanna, T; Chadwick, S; Moret, S.  Fingermark quality assessment, a transversal study of subjective quality scales.  For Sci Intl 350 (2023) 111783.

Episode 262 - Teneil Hannah Interview

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 important limitations of the study and how limited the application is to real forensic investigations.  They then explore some of the media and social media outlets that have clearly misunderstood this paper and seem to have little understanding of forensic science.  Finally, Eric and Glenn look at some quotes and comments from knowledgeable sources who also have recognized the flaws in the paper, the authors’ exaggerations, and lack of understanding of the value of their findings.

Gabe Guo et al. ,Unveiling intra-person fingerprint similarity via deep contrastive learning.Sci. Adv.10, eadi0329(2024). DOI:10.1126/sciadv.adi0329

https://www.science.org/doi/10.1126/sciadv.adi0329

https://www.engineering.columbia.edu/news/ai-discovers-not-every-fingerprint-unique

https://for-sci-law.blogspot.com/

https://www.cnn.com/2024/01/12/world/fingerprints-ai-based-study-scn/index.html

Episode 264 - Fingerprints Proven by AI to Not Be Unique!

Today Eric and Glenn finish Part 2 on the 2023 Report of the Texas Forensic Science Commission dealing with a latent print case. They continue to discuss the TFSC report that followed an investigation into a complaint filed against the latent print contractor(s) in the Joseph Webster case.  In part 2, the guys focus on Glenn's examination which concluded that the Webster palm mark was a complex mark and that 3 critical things will shape the conclusion rendered by an examiner: 1) which images were used; 2) which features were relied upon; 3) how the examiner applied the ACE-V methodology.  Finally, they discuss the over 2 dozen recommendations that the Commission made for fingerprint examiners in Texas to follow in latent print examinations.

www.txcourts.gov/media/1457617/fi…-as-of-12623.pdf

Episode 270 - The TFSC Report and the Webster Case - Pt 2

Eric 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 involvement and the fingerprint evidence.  In the second half of the show, the guys welcome Anjali Ranadive, who was the DNA expert for the defense, to discuss the DNA evidence and testimony in the case.  Both Anjali and Glenn had an opportunity to witness the DNA testimony at trial and were astounded by the “scientific conclusions” drawn, and testified to, by the DNA analyst.

Contact Anjali Ranadive: scilawforensics@aol.com

Day 1 of Trial
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-one/article_74b84328-d515-11ee-a210-8b7ef07e2631.html

Day 2 of Trial
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-two/article_eb1531e4-d5e6-11ee-ac1c-f39cc7b07d9e.html

Day 3 of Trial
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-three/article_6a7c27f2-d6b5-11ee-9124-3f5cf33a83bb.html#:~:text=The%20verdict%20is%20in%2C%20Jeremiah,on%20all%20counts%20of%20murder

Day 4 of Trial
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-four---state-rests-its-case/article_46573850-d780-11ee-a368-573401987ead.html

Day 5 of Trial
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-five/article_a1c7fbf2-d85c-11ee-8ef5-ef34bb7cdee9.html

Day 6 of Trial
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-six/article_29b37812-daa5-11ee-912e-9bf06a02bb89.html

Day 7 of Trial (Final Day)
https://www.mykxlg.com/news/local/murder-trial-of-jeremiah-peacemaker-day-seven---the-jury-is-out/article_b078ec24-db5e-11ee-bcfb-7b2eb5a1c73b.html

Verdict Announced
https://www.mykxlg.com/news/local/the-verdict-is-in-jeremiah-peacemaker-is-found-not-guilty-on-all-counts-of-murder/article_85ff1e54-db7d-11ee-b58d-27963af509b4.html

https://www.dakotanewsnow.com/2024/03/05/jeremiah-peacemaker-found-not-guilty-death-kendra-owen/

Episode 271 - SD v Peacemaker Case and Anjali Ranadive Interview

This 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) describes how the project came to be and how NIST selected the Expert Working Group (EWG).  Then, two members of the EWG, Jarrah Kennedy, Assistant DNA Supervisor, Kansas City Police Crime Laboratory, and Michelle Madrid, DNA Technical Leader, Los Angeles County Sheriff’s Department, discuss the various recommendations in the report.  The group covers all sorts of fun topics within DNA discipline such bias, new software and computational approaches, activity level, implementation, enforcement, and so forth.  The episode ends with Niki and Glenn discussing other disciplines and future reports.

Links to the free report:

Expert Working Group on Human Factors in Forensic DNA Interpretation (May 2024).  Forensic DNA Interpretation and Human Factors: Improving Practice Through a Systems Approach.  National Institute of Standards and Technology, Gaithersburg, MD, NIST IR 8503. http://doi.org/10.6028/NIST.IR.8503

https://nvlpubs.nist.gov/nistpubs/ir/2024/NIST.IR.8503.pdf


Guests:

Nikola Osborne, Ph.D., NIST Contractor, and Project Lead for the Expert Working Group.

Jarrah Kennedy, Assistant DNA Supervisor, Kansas City Police Crime Laboratory

Michelle Madrid, DNA Technical Leader, Los Angeles County Sheriff’s Department

Episode 272 - DNA and Human Factors Expert Working Group Report

Glenn and Eric are joined by Angela Hilliard to discuss her experiences with a cold case from the Pacific Northwest. Genetic genealogy provided a suspect's name from a cold case double homicide, and a latent palm print was left on the victim's van. Angela walks us through her initial erroneous exclusion, the subsequent identification, court testimony, and the resulting press coverage. A must-listen episode for examiners on how to handle erroneous conclusions, even in high-profile cases. (Apologies for the audio in this episode. We did not realize until later that some of audio was poorer quality than normal.)

Episode 273 - Angela Hilliard Interview - Erroneous Exclusions

Eric and Glenn are back from a little summer break, prepping for the 2024 IAI Conference in Reno.  They do a final “Where in the Whorld?” game.  Then they jump into a recent paper on “Inconclusive” decisions (Swofford, et al. (2024)  “Inconclusive Decisions and Error Rates in Forensic Science”, Forensic Science International: Synergy (vol 8; 100472)) authored by several members of NIST.  The paper proposes a method for computing and communicating error rates when “inconclusive” decisions are made.  The paper also focuses on making clear distinctions between “method performance” versus “method conformance”.  The guys discuss their views on the method and the implications the paper may have for fingerprint examiners and their agencies.

Swofford, H. , Lund, S. , Iyer, H. , Butler, J. , Soons, J. , Thompson, R. , Desiderio, V. , Jones, J. and Ramotowski, R. (2024), Inconclusive Decisions and Error Rates in Forensic Science, Forensic Science International: Synergy, [online], https://doi.org/10.1016/j.fsisyn.2024.100472, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957335 (Accessed August 31, 2024)

Link to open source paper here:  https://doi.org/10.1016/j.fsisyn.2024.100472

Episode 274 - NIST Inconclusive Paper

The 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 Girl Friday”, doing her impromptu interviews with conference attendees.

Episode 275 - 2024 IAI Conference: The Reno Recap

In 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!

Episode 276 - History Episode - Stories of the Forefathers

Glenn and Eric interview Sarah Chu, director of policy and reform with the Perlmutter Center for Legal Justice's (PCLJ) forensic science policy initiatives. Sarah breaks down her doctoral thesis on quality management and oversight in forensic science laboratories.

Episode 277 - Sarah Chu Interview

In 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, they discuss solutions and ideas for resolving conflict and ultimately find that conflicting results and examiner disagreements are a normal, expected, natural part of the examination process.

Find the paper at:
 https://doi.org/10.1016/j.forsciint.2024.112139

Episode 278 - Aussie Paper on Examiner Disagreements

In this episode Glenn and Eric catch up after some hectic travel from recent weather issues.  They do some news updates and also Eric had advice for new Patreon subscribers.  Then they play an Oscar-themed round of “A Truth, a Lie, and a Mandela Effect” because it is the weekend of the 2025 Oscars.  Then the guys tackle a topic which has come up many times in the past, but they’ve never actually dived into before: Simultaneous Impressions.  They talk about different scenarios that can occur such as: some impressions stand alone, none stand alone, aggregation of features, and physical gaps or voids in an impression.  They review the famous Mass v. Patterson case from 2005 that started the initial controversy in the field.  They also have a chance to discuss John Black’s JFI research article from 2006 and other source material on the subject.

Reference:
Black, J.P. Pilot Study: The Application of ACE-V to Simultaneous (Cluster) Impressions.  Journal of Forensic Identification, 56(6) Dated: November/December 2006 Pages: 933-971.



Episode 279 - Simultaneous Impressions

Eric 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.

Episode 280 - Pat Wertheim Tribute

Eric 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.

Episode 281 Kasey Wertheim Tribute

In 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



Episode 282 - Noblis-FBI Black Box 2 Fingerprint Study

Glenn 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.

Episode 283 - DNA & Patterns

In 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



Episode 284 - Black Box '22 - Part 2 (with Brendan Max)

In 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.

Episode 285 - Michael Whyte Interview - Latent to Latent Comparisons

In 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 it valid to say that there were no other beating deaths without brain or skull injuries? Was there a cleanup? Were the shorts cleaned? Were Deaver's experiments valid? What about his shirt? Quote from the episode, "People need to hear this evidence. Because I think when you watch these documentaries, you're back and forth. And if you're really suspicious of law enforcement, then you come out of this going, 'This guy got railroaded.' This guy was innocently convicted. This is a BS case. It was all on lies. But I want to go back to the evidence. I haven't seen it in 15 years, but when I saw it then, in 2002, I went, 'Oh. This is open-shut. This is clear-cut. There is no ambiguity here.'" The three big pieces of evidence were that there was an impact site on her head in space which means that someone swung an object to hit her, there was signs of a cleanup and of blood drying meaning that she was not breathing when the 911 call was made, and the blood stains on his shorts means that he was near the body when blood was flying around.

Episode 176 - The Staircase - Part 2

Glenn 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.

Episode 177 - The Staircase - Bart Epstein Interview

Glenn 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 other agencies after the error.

Episode 182 - Tucson Prime Time Rapist

In this episode, Eric and Glenn are joined by Dr. Heidi Eldridge and Prof, Christophe Champod, the authors of "Testing the accuracy and reliability of palmar friction ridge comparisons - A black box study".  The guests describe the design, the aims, and the results of the study.  We get into discussions about the meaning and usefulness of error rate statistics and confidence intervals from performance studies such as this.

Link to the Article (open source):
http://dx.doi.org/10.1016/j.forsciint.2020.110457

Link to study results in shinyapp:
https://cchampod.shinyapps.io/Results_BBStudy/

Link to confidence interval tools in shinyapp:
https://cchampod.shinyapps.io/app_CI/

Link to error rate primer prepared by Champod, Eldridge, Lambert:
zenodo.org/record/3734560#.YB8Ki5NKhbt

Episode 234 - Palm Print Black Box Study

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.

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