Genetic Genealogy and DNA Evidence - Part 3 of MK Investigates Nancy Guthrie's Disappearance
Quick Read
Summary
Takeaways
- ❖Genetic genealogy is the future of law enforcement, capable of solving cases decades old by identifying distant relatives of perpetrators.
- ❖Familial searching in CODIS, allowed in only 11-12 states like Arizona, can find near matches (e.g., father or brother) of an unknown perpetrator.
- ❖Genetic genealogy requires a different type of DNA testing (snip testing) and relies on public databases like JedMatch Pro and FamilyTreeDNA, which are smaller than private ones like 23andMe.
- ❖Mixed DNA samples, especially with minor contributors or multiple individuals, make snip testing for genetic genealogy much more challenging, sometimes "almost impossible."
- ❖DNA can be left even when wearing gloves, as perpetrators often touch their face/hair and transfer cells to surfaces.
- ❖Forensic phenotyping (e.g., by Parabon) can create a composite picture of a suspect's appearance (hair/eye color, ethnicity, facial structure) from an unmatched DNA sample.
- ❖The FBI's choice of billboard locations (AZ, TX, NM, CA, particularly Houston) suggests they may have determined the perpetrator's ethnic origin from DNA evidence.
- ❖Sheriff Nanos's public statements about knowing the motive and having strong suspicions are met with skepticism by guests due to a perceived lack of transparency and compartmentalization of information.
- ❖The theory of a transnational criminal group from South America is supported by the lack of CODIS hits, the perp's covered appearance, and a tattoo expert's analysis of the perp's wrist tattoo.
- ❖Polygraph results are either "conclusive" or "inconclusive"; the phrase "passed with flying colors" is not a recognized outcome in law enforcement.
Insights
1Genetic Genealogy Process and Challenges
Forensic DNA analyst Susanna Ryan details the steps and hurdles in using genetic genealogy. After traditional CODIS searches yield no direct match, investigators must perform 'snip testing' (single nucleotide polymorphisms) on remaining DNA. This snip profile is then uploaded to public databases like JedMatch Pro and FamilyTreeDNA to find distant relatives. The process involves skilled genealogists building family trees to narrow down potential suspects, ultimately requiring a direct comparison (traditional STR testing) for court-admissible evidence. Mixed DNA samples, especially if the perpetrator is a minor contributor or if multiple individuals are involved, significantly complicate snip testing.
Susanna Ryan explains the need for snip testing after CODIS failure and the subsequent use of public databases (), the role of genealogists in building family trees (), and the difficulty of working with mixed DNA for snip testing ().
2DNA Collection and Preservation Considerations
Ryan outlines optimal strategies for collecting DNA at a crime scene, even when a perpetrator wears gloves. She emphasizes checking points of entry/exit, doorknobs, light switches, and bedding. The MVAC, a wet vacuum instrument, can collect significantly more DNA than traditional swabbing. She also highlights the risk of 'investigator-mediated transfer,' where crime scene personnel inadvertently move DNA. DNA can last for days, weeks, months, or even years, but outdoor samples are highly susceptible to degradation and contamination.
Ryan suggests specific areas for DNA collection (), recommends the MVAC for greater DNA quantities (), warns about investigator-mediated transfer (), and discusses DNA longevity and outdoor degradation ().
3Forensic Phenotyping: Creating Suspect Composites from DNA
Megyn Kelly and Susanna Ryan discuss the capability of companies like Parabon to create a composite image of a suspect based solely on their DNA. This 'phenotyping' can predict hair color, eye color, ethnicity, and even the presence of freckles. The same snip data used for genetic genealogy is also utilized for phenotyping. This technique offers a way to generate a visual profile of an unknown perpetrator when no database match exists.
Kelly introduces Parabon's ability to create composite pictures from DNA (), showing an example of Andrea Canning (). Ryan confirms it's the same data used for genetic genealogy () and its ability to determine physical traits ().
4FBI Billboard Strategy and Suspect Ethnicity Theories
Jennifer Coffendafer, a retired FBI special agent, observed that the FBI's choice to place billboards for Nancy Guthrie in Arizona, Texas, New Mexico, and California (particularly Houston) suggests they may have determined the perpetrator's ethnic origin from DNA analysis. She posits that these states have large Mexican populations, implying the DNA contributor might be of Mexican descent. Will Gettis notes that Latin communities are often close-knit and suspicious of law enforcement, which could hinder information sharing.
Kelly references Coffendafer's observation about billboard locations and large Mexican populations (), linking it to potential DNA ethnicity determination (). Will Gettis comments on the close-knit nature and suspicion of law enforcement in Latin communities ().
5Skepticism Regarding Sheriff Nanos's Statements and Case Handling
Both Will Gettis and James Hamilton express significant skepticism about Pima County Sheriff Nanos's public statements, particularly his claim of knowing the motive and having strong suspicions from the beginning. They view his remarks as lacking credibility and substance, suggesting a high degree of compartmentalization within the investigation. Hamilton also points out that reports of 'no solid suspects' from lower-level law enforcement might stem from Nanos and his top deputies controlling all information, keeping investigators 'down the totem pole' uninformed.
Will Gettis calls Sheriff Nanos's statements 'dribble' and lacking credibility (, ). James Hamilton infers that lower-level law enforcement might be uninformed due to Nanos's compartmentalization ().
Bottom Line
The ability to create a detailed composite image of a suspect from DNA (phenotyping) without any database match could revolutionize early stages of investigations, providing leads even when genetic genealogy is not yet viable.
This means law enforcement could generate a 'sketch' of an unknown perpetrator much faster and more accurately than traditional eyewitness accounts, potentially narrowing down suspect pools significantly before any familial connections are found.
Further investment and standardization of forensic phenotyping services could become a critical first step in all cases with unknown DNA, especially where traditional databases yield no immediate hits.
The policy-driven restrictions on law enforcement accessing private DNA databases (like 23andMe) create a significant investigative hurdle, despite the potential for solving more cases.
This tension between privacy and public safety means many potential leads remain untapped, prolonging investigations and potentially leaving dangerous criminals at large. The Coberger case demonstrated that these policies can be 'bent' for extreme circumstances, but this is not standard practice.
A public-private dialogue or new legislative framework is needed to balance individual privacy concerns with the immense investigative power of these databases, potentially through opt-in systems for law enforcement access or anonymized search protocols.
Lessons
- If involved in a crime scene investigation, prioritize collecting DNA from points of entry/exit, door handles, light switches, and bedding, using advanced tools like the MVAC for maximum yield.
- Be aware of 'investigator-mediated transfer' at crime scenes; ensure strict protocols (e.g., frequent glove changes) to prevent cross-contamination of DNA evidence.
- Understand that DNA can persist for long periods (months to years) indoors, but outdoor samples degrade quickly due to environmental exposure and contamination.
Quotes
"Genetic genealogy is hot. It is the future of law enforcement. It's amazing."
"Somewhere in NY's home, there is DNA belonging to the suspect. That's what virtually every DNA expert will tell you. Like, this guy was not so forensically antiseptic that he prevented any of his DNA from getting into that home. It's just a matter of whether it can be found."
"If you have a mixture of three people or four, which is not uncommon with these type of samples, it becomes almost impossible."
"If we start seeing the same profile over and over again, we have a higher degree of confidence that we have the true perpetrator's DNA."
"There is no such thing as quote pass with flying colors end quote. That doesn't happen. Okay, that that means someone is conclusive meaning they're telling the machine is indicating that their answers are conclusive."
"We all have, you know, mothers and we all have 84 year old, you know, a lot of us have mothers of that age group and we don't want to live in a country where an 84 year old can just be taken and and no body, no leads, no nothing. This is America."
Q&A
Recent Questions
Related Episodes
Bombshell New Details About Blood Inside Nancy Guthrie’s Home | Nancy Guthrie Missing Update
"New details reveal blood patterns inside Nancy Guthrie's home match those outside, indicating no struggle, while the lead DNA lab struggles to isolate mixed samples, raising questions about the investigation's direction."
New ransom note claims to know where Nancy Guthrie is — but is it real? Day 65 in the search
"A new ransom note surfaces on the day Savannah Guthrie returns to work, raising questions about its authenticity and the ongoing, politically fraught investigation into Nancy Guthrie's disappearance."
Bombshell Details & Clues from Savannah, Police Source Reveals Inside Detail | Nancy Guthrie Case
"Savannah Guthrie reveals new details about her mother's disappearance, while a police source admits the investigation has no leads, prompting former cold case investigator Paul Holes to offer a contrarian theory of staged abduction masking a potential homicide."
Breaking: Location of Blood Inside Nancy Guthrie's Home Revealed | Nancy Guthrie Missing Update
"New forensic details reveal Nancy Guthrie's blood was found inside her home's front entrance, extending outside, indicating a stationary bleeding event, while Sheriff Nanos faces a no-confidence vote for his handling of the investigation."