Double Loop Podcast
169 episodes - English - Latest episode: 4 days ago - ★★★★★ - 69 ratingsWhether 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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Episodes
The TFSC Report and the Webster Case - Pt 2
April 22, 2024 00:00 - 1 hour - 70.3 MBToday 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 ...
Episode 269 - The TFSC Report and the Webster Case - Pt 1
April 08, 2024 00:00 - 59 minutes - 49.8 MBToday 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...
Episode 268 - Steve Johnson Interview
March 21, 2024 05:35 - 49 minutes - 45.5 MBEric 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.
Episode 267- Chloe George Interview - Research on Phalange Patterns
March 09, 2024 00:00 - 52 minutes - 43.8 MBEric 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 a...
Episode 266 - Andy Chapman Interview - Aussie Black Box Study
February 17, 2024 00:00 - 56 minutes - 48.6 MBIn 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, esp...
Episode 265 - Dr. Bethany Growns Interview
February 02, 2024 00:00 - 55 minutes - 47.4 MBGlenn 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 an...
Episode 264 - Fingerprints Proven by AI to Not Be Unique!
January 20, 2024 00:00 - 1 hour - 81.4 MBEric 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 do...
Episode 263 - Caitlin Rough Interview
January 12, 2024 00:00 - 47 minutes - 39 MBIn 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 ...
Episode 262 - Teneil Hannah Interview
December 29, 2023 00:00 - 56 minutes - 78.3 MBEric 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 tech...
Episode 261 - Fall Travel Catchup
December 19, 2023 05:39 - 58 minutes - 53.8 MBGlenn 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?)
Episode 260 - Tales from the Courtroom
November 25, 2023 00:00 - 1 hour - 112 MBEric 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 259 - The 2023 IAI Conference
September 22, 2023 00:00 - 1 hour - 104 MBEric 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 258 - Gap Science Interview
September 15, 2023 07:50 - 32 minutes - 29.5 MBEric 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 con...
Episode 257 - Which Forensic Discipline Is The Most Reliable?
August 13, 2023 00:00 - 1 hour - 109 MBTo 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...
Episode 256 - Tom Busey - CSDIAI
July 20, 2023 07:39 - 1 hour - 108 MBGlenn 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.
Episode 255 - Busey Visual Evidence Paper
June 12, 2023 18:53 - 51 minutes - 47.5 MBEric 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.
Episode 254 - NIST Latent Accuracy
April 03, 2023 05:11 - 54 minutes - 50 MBGlenn 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 al...
Episode 253 - Bigger Blacker Boxes
February 21, 2023 06:39 - 1 hour - 62.3 MBEric 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.
Episode 252 - Alan McNamara Interview
February 08, 2023 08:34 - 1 hour - 81 MBGlenn 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.
Episode 251 - Alan McNamara Case - Part 2
January 14, 2023 22:37 - 1 hour - 72.5 MBEric 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...
Episode 250 - Alan McNamara Case - Part 1
January 06, 2023 07:49 - 1 hour - 62.9 MBGlenn 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 249 - IAI 2022 & Catch Up Episode
December 07, 2022 00:00 - 52 minutes - 71.5 MBEric and Glenn return from a hiatus to have a more relaxed catch-up episode. They share an adventure or two including the great Arizona Treasure Hunt that they participated in. Eric shares some experiences from the User Conference he worked. And finally the guys talk about the Double Loop Podcast booth experience at the 2022 Omaha IAI Educational Conference. They play a bunch of clips and recordings from our “Correspondent” Rebecca Coutant who was running the booth and playing “(Wo)Man on...
Episode 248 - Dr. Henry Swofford Interview
August 11, 2022 00:00 - 1 hour - 73.8 MBEric and Glenn interview returning guest, and newly minted PhD, Dr. Henry Swofford on his recent paper, with co-author Prof. Christophe Champod: “Probabilistic reporting and algorithms in forensic science: Stakeholder perspectives within the American criminal justice system” (For Sci Intl Synergy 2020; https://doi.org/10.1016/j.fsisyn.2022.100220). The new article discusses interview responses from judges, prosecutors, defense attorneys, scholars, and forensic laboratory managers regarding ...
Episode 247 - Brianne Breedlove Interview
June 29, 2022 17:54 - 1 hour - 73.1 MBGlenn 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.
Episode 246 - Stephan Cowans Case
May 07, 2022 00:00 - 1 hour - 101 MBToday, 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 r...
Episode 245 - Errors and CVs and Disclosure
March 31, 2022 07:34 - 1 hour - 65 MBEric 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.
Episode 244 - Hillary Moses Daluz Interview
February 05, 2022 00:00 - 56 minutes - 77 MBIn this episode, the guys interview fingerprint examiner, multi-book author, and instructor, Hillary Moses Daluz . Hillary discusses her new book "Courtroom Testimony for the Fingerprint Examiner" (CRC Press; 2021). They discuss some of the difficult hot topics that examiners struggle with during testimony and how keep testimony training positive and optimistic.
Episode 243 - New Years Grab Bag
January 31, 2022 08:10 - 1 hour - 55.1 MBEric 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!
Episode 242 - Review of ASB Documents 2021
December 27, 2021 00:00 - 1 hour - 85.1 MBIn this episode, the guys talk about Thanksgiving: Eric’s amazing food preparation and Glenn’s travel to Canada to teach. Eric also gives a plug for Kasey Wertheim’s fingerprint book library that is up for auction. In the main segment, they discuss two of the new ASB proposed standards out for public comment. Specifically, they examine differences with these documents and those proposed by OSAC, noting the pros and cons between the two versions. They discuss the ASB 013 – “Standard for Fr...
Episode 241 - Blind Proficiency Testing Paper
December 01, 2021 08:15 - 55 minutes - 50.6 MBEric 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 ...
Episode 240 - Todd Weller returns to discuss inconclusives
October 21, 2021 00:00 - 1 hour - 63 MBThe long awaited/dreaded return of the “Dad Joke Intro”! In this episode, Todd Weller (firearms expert) returns to the show to talk to Eric and Glenn about the article on inconclusive decisions by Itiel Dror and Nicholas Scurich [(Mis)use of scientific measurements in forensic science; Forensic Science International, 2020; 2:333-338]. Todd gives his views on how the article mischaracterizes the error rate computations and designs of various firearms studies. The guys try to relate it back ...
Episode 239 - 2021 IAI Conference
September 27, 2021 01:14 - 36 minutes - 33.7 MBReturn with Glenn and Eric to the IAI Conference in Nashville, TN. The guys are joined by Josh Connelly, Kurt Aebersold, JP Rodriguez, and Claudine Carter Pereira. New accuracy studies, open field research, and stat talk. And we're already looking forward to next year's conference in Nebraska!
Episode 238 - Dror and Scurich Article
July 06, 2021 16:14 - 1 hour - 69.7 MBGlenn 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 sug...
Episode 237 - Testifying After an Error
April 25, 2021 23:45 - 1 hour - 67.2 MBGlenn 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 ...
Episode 236 - Mindset Paper (Eldridge & Champod, Part Deux!)
March 27, 2021 00:00 - 1 hour - 60.8 MBIn this episode, the guys return for Round 2 with Dr. Heidi Eldridge and Prof. Christophe Champod. This time, they discuss the second paper arising from the palm print black box study (discussed in DLP Episode #234). The focus in this episode is “Mind-set – How bias leads to errors in friction ridge comparisons” by Eldridge, de Donno, and Champod in Forensic Science Int’l 318 (2021). This paper explores how instances of false positives and false negatives may have resulted from cognitive b...
Episode 236 - Mindset Paper (Palms Part Deux!)
March 25, 2021 00:00 - 1 hour - 60.8 MBIn this episode, the guys return for Round 2 with Dr. Heidi Eldridge and Prof. Christophe Champod. This time, they discuss the second paper arising from the palm print black box study (discussed in DLP Episode #234). The focus in this episode is “Mind-set – How bias leads to errors in friction ridge comparisons” by Eldridge, de Donno, and Champod in Forensic Science Int’l 318 (2021). This paper explores how instances of false positives and false negatives may have resulted from cognitive b...
Episode 235 - Todd Weller Interview
March 12, 2021 18:18 - 1 hour - 89.6 MBGlenn 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.
Episode 234 - Palm Print Black Box Study
February 26, 2021 00:00 - 1 hour - 81.3 MBIn 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.forsci...
Episode 233 - GYRO Accuracy Paper
February 16, 2021 07:52 - 1 hour - 63.5 MBGlenn 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 algorit...
Episode 232 - Differing Conclusions Article
January 06, 2021 08:02 - 1 hour - 81.6 MBGlenn 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.
Episode 231 - Review of Carter, et al. (2020) Paper on Conclusion Scales
November 24, 2020 00:00 - 1 hour - 64.6 MBAfter some Halloween talk, Eric and Glenn discuss this episode’s research article: “The Utility of Expanded Conclusion Scales During Latent Print Examinations” by Carter, Vogelsand, Vanderkolk, and Busey in J Forensic Sciences (online, 2020). This study examines the results of 27 experts who completed 30 comparisons under a 3-point SWGAST scale versus 30 comparisons under a 5-point OSAC scale. The guys discuss error rates, changes in apparent decision thresholds, and the rate of misleading ...
Episode 231 - Conclusion Scales Article
November 23, 2020 00:00 - 1 hour - 64.6 MBAfter some Halloween talk, Eric and Glenn discuss this episode’s research article: “The Utility of Expanded Conclusion Scales During Latent Print Examinations” by Carter, Vogelsand, Vanderkolk, and Busey in J Forensic Sciences (online, 2020). This study examines the results of 27 experts who completed 30 comparisons under a 3-point SWGAST scale versus 30 comparisons under a 5-point OSAC scale. The guys discuss error rates, changes in apparent decision thresholds, and the rate of misleading ...
Episode 230 - Fingerprint Error Rate in Close Non-Matches
October 28, 2020 00:00 - 1 hour - 78 MBIn this Halloween episode, Eric and Glenn discuss a new paper published by Koehler and Liu titled “Fingerprint error rate on close non-matches” (Journal of Forensic Sciences, Sept. 2020). The paper raises a lot of discussion between the guys regarding close non-matches, inconclusives, training, and testimony. They each have a different take on some of the key issues in the paper, but in the end identify what common ground on which they agree.
Episode 229 - Bob Garrett
October 13, 2020 07:17 - 1 hour - 75.9 MBGlenn 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 ...
Episode 228 - Knuckle-Crease Daubert Hearing
September 16, 2020 00:00 - 1 hour - 82.7 MBIn this episode, Glenn and Eric discuss a recent case Glenn was involved in: a knuckle-crease case. The case had a Daubert hearing in addition to trial testimony for jurors. The guys discuss if non-friction ridge skin associations would meet the Daubert factors. If you were preparing for such a hearing, what research and testing would you need to demonstrate expertise of the expert, or demonstrate reliability of the methods and principles? Does expertise in fingerprints using ACE-V transl...
Episode 227 - NY Firearms Case
September 02, 2020 08:30 - 1 hour - 73.5 MBGlenn 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...
Episode 226 - Best Latent Print Books
July 20, 2020 06:28 - 1 hour - 56.7 MBGlenn 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/b39pp6j
Episode 225 - The Most Dangerous Animal of All Documentary
July 01, 2020 00:00 - 1 hour - 85.1 MBThis week, the guys review and share their reactions to the documentary “The Most Dangerous Animal of All” (produced by Campfire Productions and available now on F/X and Hulu). This is a story about Gary Stewart who believes his father, Earl Van Best, Jr. was the infamous Zodiac Killer in San Francisco in the 1960s/1970s. The series reveals who Gary is and his obsession with the Zodiac. Then it shows all of the extensive evidence that he and his co-author accumulate to prove Earl Van Best ...
Episode 224 - Forensics in the New Normal
June 16, 2020 07:46 - 1 hour - 67 MBGlenn 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.
Episode 215 - Aging Latent Prints
June 02, 2020 00:00 - 55 minutes - 50.6 MBEric and Glenn wrap up their “activity level series” by discussing two articles (Girod, et al. 2016; and Hinners, et al. 2020) which propose determination of aging of latent fingerprint residue. The techniques use instrumental techniques to identify breakdown products of various fatty components in latent print residue, and use these results to classify whether a latent print is a couple of days old, or older (up to a week or month old depending on the paper). This is a nice finale to the s...