Double Loop Podcast

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

Today Eric and Glenn start Part 1 of a two-parter on the 2023 Report of the Texas Forensic Science Commission dealing with a latent print case. First the guys do some catching up and play Where in the Whorld. They also discuss an email from Simon Cole and inquire on the impact of the recent AI paper on fingerprints. Then they discuss the TFSC report that followed an investigation into a complaint filed against the latent print contractor(s) in the Joseph Webster case. The webster case was a homicide cold case that eventually broke with a CODIS hit and a subsequent apparent bloody palm print at the scene of the crime. Initially the palm print was not identified to Webster, but then after the CODIS hit occurred to Webster and a second person, the latent print evidence was re-visited in 2013, and an identification was declared (pursuant to reviewing additional palm print exemplars of Webster). Testimony occurred in 2016 by a project manager, but not any of the original examiners. In 2020, a contractor for

Eric 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.

Eric 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 presentation can be found here: https://docs.google.com/presentation/d/1yrUsOFM5alJV1rQcrTGXiQkDb-3DuWUO/edit#slide=id.p5

In this post-New Year’s Eve 2023-2024 episode, the guys start by discussing their New Year’s Eve and play another round of Where in the Whorld. They then introduce their guest from the New South Wales Police Force, Andrew Chapman. Glenn had the benefit of seeing Andy’s presentation at IAFS in Sydney. Andy presented on a fingerprint black box error rate study conducted with laypeople, trainees, and experts in New South Wales, Australia. The guys discuss various statistics in the study, especially when comparing across the participant groups. The Aussie data are very similar to U.S. examiner data and the guys draw some parallels to other research. The guys also discuss some novel aspects to the study design that make this one such a fascinating study.

Glenn and Eric start by talking about their Christmas plans, followed by a game of “Where in the Whorld”. They then welcome their guest, Dr. Bethany Growns, a lecturer and psychologist at the University of Canterbury, in New Zealand. Bethany joins the show to discuss her research on matchers, super-matchers, and research she has conducted with novices (lay people), fingerprint, firearms, and facial recognition experts. She discusses the advantages of natural ability v. trained expertise and how it impacts one’s ability to perform matching tasks in the expert’s domain v. other domains. The guys ask questions about how to utilize this research to impact training programs. Finally, they discuss more aspects of the IAFS conference where Glenn met Bethany. Growns B, Dunn JD, Mattijssen EJAT, Quigley-McBride A, Towler A. Match me if you can: Evidence for a domain-general visual comparison ability. Psychon Bull Rev. 2022 Jun;29(3):866-881. doi: 10.3758/s13423-021-02044-2. Epub 2022 Jan 7. PMID: 34997551; PMCID

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 hav

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

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

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

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

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

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

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

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

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

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

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

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

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