The Knife: A True Crime Podcast

Special Episode: Solving Cold Cases with DNA (October 21, 2025)

Overview

In this special episode, hosts Hannah Smith and Patia Eaton are joined by Aylin Lance Lesser, host of America's Crime Lab, for a deep dive into how new DNA technology — particularly genetic genealogy — is solving decades-old cold cases. Through a blend of scientific explanation and gripping true crime storytelling, the episode explores the evolution of forensic DNA, focusing on a landmark case: the 1974 murder of Carla Walker in Fort Worth, Texas. The discussion not only covers the technical details and ethical implications of modern forensic science but emphasizes the heavy emotional toll unsolved crimes take on families and communities.

Key Discussion Points & Insights

1. Origins of America’s Crime Lab and Aylin’s Involvement

• Aylin explains her entry into true crime journalism and her role in the launch of the podcast in collaboration with Kaleidoscope, iHeart, and Othram Labs.
  “It was one of those providential things… They were like, we want this information to go out into the public because the more people know about it, the more detectives across the country could reach out to Othram and use the technology. A huge barrier to it being used is people just not knowing about it.” (04:43)

2. DNA Technology: From Traditional to Genealogy-Based Methods

• Old vs. New DNA Testing:
  • Traditional DNA profiling examined 20 genetic markers, cross-referenced against the CODIS database — limited to known offenders.
  • New techniques (as pioneered by labs like Othram) use 100,000–1,000,000 markers, enabling searches in genealogical databases (with user consent).
  • This expanded data set allows investigators to build family trees and follow leads, even when perpetrators aren’t in CODIS.
• Notable Quote:
  “With the new technology… you can use genealogical websites to build out a family tree… and whittle down, often to a single name… It’s not a slam dunk. It doesn’t mean you have a conviction. It’s just giving you a name to investigate.” — Aylin Lance Lesser (07:36)
• CODIS is distinct from genealogical databases:
  “I’m glad you clarified that — CODIS is the old standard, 20 marker profile. And this is using information from genealogical websites… So it could be anyone off the street.” — Aylin Lance Lesser (11:22)

3. Case Study: The 1974 Carla Walker Murder

Carla Walker — Her Story and Disappearance (13:18–18:32)

• Carla was a beloved 17-year-old in Fort Worth, Texas, described as spunky and caring.
• After a school dance, Carla and her boyfriend, Rodney, were attacked in a parking lot. Rodney was assaulted and lost consciousness; Carla was abducted and later found murdered.
• The community and her family endured decades of grief and uncertainty.

The Investigation and Decades of Suspicion (18:32–29:56)

• Investigation centered initially on Rodney; suspicion compounded by an unexplained gap in his timeline after the attack.
• Rodney continued to be a suspect but also remained close to Carla’s family. Eventually, suspicion and grief compelled him to move away.
• Other suspects included local men with access to a specific type of gun and even a false confession. However, all leads stagnated; the case went cold for 46 years.
• Notable Quote:
  “It’s a good reminder too, in general, when we talk about crimes: you don’t know what people’s motivations are for really weird or unusual behavior. And that’s why the evidence itself is so important.” — Aylin Lance Lesser (28:58)

The Breakthrough: Community Action and Forensic Innovation (32:42–38:25)

• In 2020, a group of local women, the “Cowtown Cold Case Chicks,” assembled their own case file and caught the attention of famed investigator Paul Holes at CrimeCon.
• Initial DNA testing consumed much of the available evidence without results, leading to despair for the investigators and community.
  “Once you test [DNA], you can’t test it again. And if you somehow fail with the analysis, then you’re just left with nothing.” — Aylin Lance Lesser (36:14)
• Othram Labs, moved by a TV special on the case, requested even a minuscule, degraded DNA sample. Their advanced techniques succeeded where others had failed.

Identification and Arrest of Glenn Samuel McCurley Jr. (41:58–51:18)

• Genetic genealogy narrowed the suspect pool, pointing to McCurley, who lived in the community for decades as a seemingly upstanding citizen.
• Investigators approached him under the guise of a wellness check and requested a DNA sample, poking holes in his attempted alibi (with his own wife inadvertently exposing inconsistencies).
• His DNA matched the crime scene; further investigation recovered the murder weapon hidden in his home.
• Polygraph tests and old investigative standards proved unreliable.
• Notable Moment:
  “[McCurley] immediately throws up his hands and says, ‘Oh, it wasn’t me.’ Basically joking.” — Aylin Lance Lesser (45:03)
  “His wife, who’s sitting elsewhere in the room… says, ‘Oh, now you’re wrong about that. I was out of town that weekend.’ …So his alibi is shot.” — Aylin Lance Lesser (46:15)
• Though initially denying guilt and preparing to plead not guilty, McCurley changed his plea to guilty before trial, finally resolving the case.

Suspicion of Additional Crimes (51:35–54:08)

• McCurley’s confessions contained suggestive details, leading detectives to suspect involvement in other unsolved attacks or murders.
• Despite living quietly for decades after the crime, experts and hosts agree it’s unlikely such a violent first offense came out of nowhere.

4. Broader Impact: The Importance of Cold Case Resolution

• Effects on Families and Communities:
  “Cold cases don’t just go away … it stays with people. People really care about resolution. It means a lot … to have that answer.” — Hannah Smith (24:56)
• This technology not only gives closure to families but may prevent future violent crimes by identifying perpetrators before they reoffend.

5. A Silent Epidemic: Unidentified Remains (57:43–60:09)

• Tens of thousands of sets of unidentified human remains exist in the US; many families wait decades for answers.

• Labs like Othram are working, often in partnership with law enforcement and legislators, to identify these remains and resolve unsolved disappearances.

• Notable Quote:
  “There are tens of thousands of remains existing in the US that are simply unidentified. And for each one of those people, you know, there’s a family, a community, friends who have lost that person and just have no idea what happened to them.” — Aylin Lance Lesser (58:04)

Notable Quotes & Memorable Moments

• On Genetic Genealogy:
  “It creates a lead. It’s not a slam dunk. It doesn’t mean you have a conviction…You have to go back and do your due diligence, figure out if the person has an alibi, …and really do the good old fashioned detective work.” — Aylin Lance Lesser (07:36)

• On Rodney and Cold Case Suspicion:
  “When you don’t have hard evidence, anybody can become a suspect, and… it can tear towns apart and families apart.” — Hannah Smith (54:49)

• On Community Efforts:
  “What I love is the idea of just these people coming out of the woodwork… They’re coming from all walks of life… but they’re brought together from this case and somehow just feeling this emotional connection to it.” — Aylin Lance Lesser (34:00)

• On the Emotional Toll:
  “Jim, Carla’s younger brother… actually… kept the family home throughout his adulthood in hopes that maybe someone who knew something would come and tell him what happened.” — Aylin Lance Lesser (20:59)

Timestamps for Key Segments

• [04:43] — Aylin on the origins of America’s Crime Lab
• [07:36] — Layman’s explanation of advanced DNA technology
• [13:18] — Carla Walker’s story and the night of her abduction
• [18:32] — Early investigation: evidence and suspicion of Rodney
• [24:28] — Rodney leaves town; lasting effects and community suspicion
• [32:42] — The Cowtown Cold Case Chicks and Paul Holes get involved
• [36:14] — The risk of consuming all available DNA in failed testing
• [38:25] — Othram Lab’s breakthrough: extracting a usable DNA profile
• [41:58] — The family tree points to Glenn McCurley; step-by-step arrest
• [47:12] — Double-checking results with both old and new DNA methods
• [49:19] — Discovery of the murder weapon in McCurley’s home
• [54:08] — Suspicions of McCurley’s involvement in further crimes
• [57:43] — The “silent epidemic” of unidentified remains in America

Language & Tone

The episode is empathetic, reflective, and deeply respectful of both the science and the people impacted by crime. The hosts and guest speak accessibly about complex forensic topics, without sensationalism. Where technical concepts arise, they are broken down into layperson’s terms, often with humor and humility (“There’s a reason I’m a podcaster and not like, a scientist” — Hannah Smith).

Summary

This episode underscores the transformative power of new DNA and genetic genealogy technologies to solve the unsolvable, while never losing sight of the victims and communities left in the wake of unsolved crimes. Through the lens of Carla Walker’s case, it provides a nuanced look at science, justice, and the human need for answers — all delivered with the warmth and curiosity that define The Knife.

Listen for compelling first-person accounts, inside perspectives on forensic breakthroughs, and thoughtful reflections on the ethical and emotional dimensions of solving cold cases.