The Clues That Solved the Unsolvable | Forensic Files

Imagine a case that's been cold for decades. No leads, no suspects, families left without answers.
And then suddenly, one tiny bit of DNA changes everything. Thanks to cutting-edge science, we're seeing more
breakthroughs in cases than ever before. And it's mostly because of DNA. So now,
I'm breaking down five powerful types of DNA testing that investigators use to solve crimes and sharing the real cases
where [music] those tests uncovered the truth. Starting off with number five. Investigative genetic genealogy, [music]
or IGG. You probably heard a lot about IGG in recent years. But what is it exactly? Investigative
genetic genealogy brings forensic DNA analysis together with traditional genealogy to develop leads in criminal
investigations or to identify unidentified human remains. Investigative genetic genealogists or
members of law enforcement can upload DNA profiles from a crime scene or from remains to certain genetic genealogy
databases. And from there, they work on identifying genetic relatives of the person whose DNA they have and build out
a family tree with that data. After the family tree has been built out, police potentially look to obtain a DNA sample
from someone in that family tree to compare against the original sample. One notable case that has been solved in
part thanks to IGG is the murder of April Marie Tinsley. April was just 8 years old when she was kidnapped,
sexually assaulted, and murdered in the spring of 1988. Biological evidence was collected at the
scene, but sampling and testing protocols weren't advanced enough yet to solve the case. But by the early 2000s,
investigators were finally able to pull a DNA profile from the sample and upload
it to CODIS. But no matches [music] were immediately found. That meant that it was likely that the perpetrator's DNA
had never been uploaded to the CODIS database in connection to any other crimes.
So the case sat cold until 2018, >> [music] >> when investigators retested the sample
that they had to get a profile suitable for GEDmatch, which is a public opt-in DNA database. Seriously, anyone,
including you, can upload DNA to GEDmatch. From there, genealogist CeCe Moore used family tree mapping to
identify John D. Miller, who had lived not too far from April at the time of her murder. Investigators knew Miller
probably wouldn't turn over his DNA sample for direct comparison willingly. So they collected his abandoned DNA by
obtaining used condoms from his trash. Then, when they did a direct comparison to the sample they had in April's case,
they found out it was indeed their guy. In 2018, John Miller pled guilty to murder and child molestation in
connection with April's killing. He was sentenced to 80 years in prison. So though it took some time and
technological advances, DNA led to justice for April. Number four. Familial searching. What if solving a
case didn't come down to the killer's DNA, but their relatives? That's the idea behind familial searching. Instead
of looking for a perfect match in CODIS, the US national DNA database, investigators look for partial matches.
[music] DNA that might belong to a parent or sibling or child of the suspect. Now,
CODIS and how it works is a beast all on its own. So if that's something that you
want to dive deeper into in a separate video, be sure to like this one. Let me know what about CODIS you want to learn
more about in the comments below. [music] I'm doing a deep dive. But familial searching helps
investigators identify potential relatives of people whose DNA was collected from a crime scene.
It doesn't necessarily lead investigators straight to their suspect, but it may help them find a close
relative of their suspect. [music] And in order to get that sort of hit, that relative's DNA has to have already
existed in the DNA database, whether that's [music] by choice or because they have committed a crime. Now, there are
laws around this type of testing in some states because of privacy concerns. A state that approves the use of
familial searching to find suspects is New York, where the murder of Wendy Jerome occurred in 1984. Multiple
samples in varying degrees of degradation had been found at the scene of Wendy's murder. And they were all
tested multiple times in multiple ways. Until finally, in 2020, a test of one of
the samples led to a familial hit in CODIS. >> [music] >> That hit was for a relative of Timothy
Williams, the man we now know was responsible for Wendy's killing. His conviction made history because it was
the first case in New York state to be solved using familial DNA testing. Number three. Mitochondrial DNA, or
mtDNA analysis. How do you catch a killer when the only evidence left behind is a single strand of hair
without a root? That's where mitochondrial DNA, or mtDNA analysis, comes in. This type of DNA is pulled, as
the name suggests, from mitochondria, and it's always passed down from mother to child. Many people share the same
mtDNA, so it cannot be used to identify unique individuals. But it can link someone to a maternal line. And because
it works even when DNA is too degraded for other tests, it can give investigators a critical lead when other
methods can't. That's exactly what happened in the search for the Gilgo Beach killer. Investigators found
degraded, rootless hairs on the burlap sacks used to wrap some of the victims up in this case.
And by 2023, a lab was able to successfully pull an mtDNA sequence from the hairs.
Now, there are several ways to do this, and we don't know exactly what method they used because they've not made that
public yet. Probably because this case is still going to trial, maybe. But they extracted DNA from those hairs and used
whole genome sequencing to develop a profile. Then they used that sequence to narrow down a pool of possible families,
including the family of Long Island man Rex Heuermann. This mtDNA sequence was then compared against a reference sample
that had been obtained from a pizza crust that officials say Rex Heuermann had thrown away, which is another
example of voluntarily abandoned DNA. That allowed them to get a warrant, collect a buccal swab, and then
establish a direct match. Heuermann was charged with murder in the deaths of at least seven women spanning
three decades. One thing I do want to note about mtDNA evidence is that it is rarely the only evidence used to
prosecute someone. It doesn't prove identity by itself, remember, but it can be the crucial piece that backs up other
evidence and helps prosecutors close in on a suspect. Number two. Y-STR DNA. Now, this type of testing zeros in on
one thing and one thing only, the Y chromosome, which only exists in men. So it can only trace DNA passed down from
father to son. This type of testing can be particularly powerful when evidence has a mix of male and female DNA, like
for example, what could be present in a sexual assault kit. By isolating the Y chromosome, labs can
pull out just the male DNA from the sample. >> [music] >> One chilling example of this? The 1991
yogurt shop murders in Austin, Texas. [music] At the time, Y-STR testing was brand
new. And the district attorney overseeing the case decided to give it a shot. Investigators believed that at
least one of the victims in this case had been sexually assaulted. And this test paid off. They pulled a partial
male DNA profile from the evidence. >> [music] >> But in the '90s, that profile didn't
match anyone in the system, so the case went cold. Decades later, in 2025, everything changed when police received
a report from a South Carolina state lab that linked the yogurt shop unknown Y-STR profile to a known Y-STR profile
from a 1990 sexual assault and murder out of Greenville. The suspected killer? Robert Eugene Brashers, a known serial
rapist and killer who had taken his own life back in 1999. From there, investigators were able to
use other evidence to connect Brashers to the yogurt shop murders, bringing long-awaited answers to a case that
haunted Texas and us crime junkies for more than 30 years. Number one. Short tandem repeat, or STR analysis.
When it comes to solving crimes with DNA, this is the gold standard. STR analysis, short tandem repeat testing,
[music] compares short, repeating DNA sequences between a DNA sample giver and DNA evidence collected from a crime
scene. It's powerful because it gives investigators a yes or no answer. Either it is a match or it's not.
STR analysis can be used to identify men or women, as it examines DNA patterns found within the human genome. It is the
only type of DNA analysis that can be used to convict someone in court because it's a one-to-one comparison. [music]
And because STR analysis either finds a direct match or no match at all, it can also be used to exclude individuals from
a suspect list. And one of the most infamous cases cracked by STR? The hunt for the Green River Killer.
Some detectives originally working the case, even back in the day, recognized the potential power of DNA. And so they
held on to DNA evidence even though they couldn't do anything with it in that moment. But they figured that could
change as technology continued to advance. And sure enough, in the case of the Green River Killer, that paid off.
Gary Ridgway first came onto police's radar in 1983. And in 1987, they eventually had enough evidence to search
his home in connection to their investigation. And during that time, police took samples of Ridgway's hair
and saliva. Again, even though DNA testing was still in its infancy. Fast forward to 2001, technology had
advanced and investigators finally had what they needed and they were able to directly compare Ridgway's DNA to a
sample pulled from a Green River victim via STR analysis. The original STR analysis was compared to sperm found on
three victims: Cynthia Cookie Gene Hines and Marcia Faye Chapman, [music] discovered on August 15th, 1982. And
then Carol Anne Christensen, found May 8th, 1983. After nearly two decades of unanswered questions, the Green River
Killer was brought to justice. Ridgway was convicted and sentenced to life in prison.
These are just some of the cases where though it may have been delayed, justice was served through the help of DNA
testing. If you want to go deeper into any of these, you can find the full stories on Crime [music] Junkie wherever
you get your podcast, including right here on YouTube. Don't forget to like, subscribe, and hit
the bell so you never miss our next investigation.

Imagine a case that’s been cold for decades, no leads, no suspects, and families left without answers. Then one piece of DNA changes everything. In this video, Ashley Flowers breaks down five powerful types of DNA testing that investigators use to solve crimes and real cases where those methods led to breakthroughs.

#5: Investigative Genetic Genealogy (IGG) A technique that combines DNA analysis with family tree research to identify suspects through relatives. Featured case: April Marie Tinsley (Fort Wayne, Indiana, 1988)

#4: Familial DNA Searching Instead of a perfect match, investigators look for partial matches to relatives in DNA databases. Featured case: Wendy Jerome (Syracuse, New York, 1984)

#3: Mitochondrial DNA (mtDNA) Used when traditional DNA is too degraded, especially helpful with hair samples. Featured case: Gilgo Beach investigation (Long Island, New York, 1990s–2010s)

#2: Y-STR Testing Focuses on male DNA to isolate profiles in mixed samples. Featured case: Austin Yogurt Shop Murders (Austin, Texas, 1991)

#1: STR Analysis (Short Tandem Repeat) The gold standard of DNA testing, used to confirm exact matches. Featured case: Green River Killer,Gary Ridgway (Washington State, 1980s–2001)

From decades-old cases to modern investigations, these methods have transformed how crimes are solved, turning tiny biological clues into powerful evidence.

Key Episode Moments: 00:00 Intro 00:31 Investigative Genetic Genealogy (I-G-G) 2:59 Familial Searching 4:46 Mitochondrial DNA, or mtDNA Analysis 6:48 Y-STR Database Searching 8:29 Short Tandem Repeat, or STR Analysis -------- Follow Crime Junkie: Instagram: https://www.instagram.com/crimejunkiepodcast Facebook: https://www.facebook.com/CrimeJunkiePodcast/ Twitter: https://twitter.com/CrimeJunkiePod Crime Junkie is created and hosted by Ashley Flowers.

About Ashley Flowers Ashley Flowers is the top female podcaster in the U.S. and the host of Crime Junkie, the #1 podcast among women and the #1 true crime podcast globally. As the Founder of Audiochuck, she has built a top-tier podcast production company that has garnered over 2.6 billion downloads, captivating audiences with its gripping storytelling through 10+ chart topping podcasts. Ashley and her team are dedicated to creating responsible true crime content that respects victims and their families.

Follow Ashley: Instagram: https://www.instagram.com/ASHLEYFLOWERS/ Twitter: https://twitter.com/ash_flowers TikTok: https://www.tiktok.com/@ashleyflowerscrimejunkie Facebook: https://www.facebook.com/ashleyflowers.af/

Check out these other great crime channels: @annieelise If Looks Could Kill: The Murder-For-Hire Case of Tara Lambert https://www.youtube.com/watch?v=d30lOKqRvoA @kallmekris This 37-Year-Old Cold Case Was SOLVED By The Internet https://www.youtube.com/watch?v=eQiqTxBBjIQ @KendallRae Police Find Murder Plot Crumpled In Trash?! The Case Of Patrick De La Cerda https://www.youtube.com/watch?v=zaSUhwtjJvw @bellafiori The Twisted Case of Dan Markel https://www.youtube.com/watch?v=v45cDjLN6ZQ

Brief Summary

The episode discusses five DNA testing methods that solved cold cases, including IGG and STR analysis.

Key points

The Power of DNA Testing. Explore how DNA testing has revolutionized crime-solving, leading to breakthroughs in cold cases.
The Murder of April Marie Tinsley. A chilling case solved through investigative genetic genealogy after decades of silence.
Familial Searching Breakthrough. The first case in New York solved using familial DNA testing brings justice to Wendy Jerome.
The Gilgo Beach Killer. Mitochondrial DNA analysis links evidence to a suspect in a high-profile case.
The Green River Killer's Justice. After nearly two decades, DNA evidence finally brings the Green River Killer to justice.

Episode highlights

Episode quotes

One tiny bit of DNA changes everything.

0:06WatchApr 22, 2026

Tension

65/ 100Some tension

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