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5 Common Myths About Genetic Genealogy Investigations

By police personnel1

While the use of genetic genealogy to ultimately solve the Golden State Killer case was a watershed moment for investigations that we have named him one of our key game changers in law enforcement. 2010s, police use of direct-to-consumer services FamilyTreeDNA and GEDmatchPro has not been without bumps in the road. The new solution for tackling cold cases has arguably been a magnet for controversy ever since Golden State Killer’s breakthrough hit the headlines. Foremost among these concerns are privacy issues, even leading some states to push back on how law enforcement agencies can use genetic genealogy services. There is a lot of information circulating about police use of this investigative technique, and some of the most often repeated sentiments are wrong.

Stephen Kramer and Stephen Busch, who co-founded the FBI’s Forensic Genetic Genealogy (FGG) team, recently hosted an ISHI webinar titled “An Inside Look at the Facts and Fiction Surrounding Genetic Genealogy”, in which they highlighted repeatedly the importance of “protecting the technique.” Along with being thoughtful and careful in how investigative techniques are used, one of the other essential steps in keeping things like FGG from being criticized to an unmanageable degree is to dispel myths and misinformation. Among the topics covered by Kramer and Busch were five common myths about the use of genetic genealogy in investigations. People tend to fear what they don’t understand, and it’s important to know where misunderstandings lie and how to resolve them. Here is an overview of these misconceptions and facts.

Myth #1: LE can (and will) use this technique to investigate any type of crime.

A common misconception is that genetic genealogy is leveraged for all crime and investigative work. The FGG is used for high priority cases such as crimes involving serious violence such as homicide and rape, as well as ongoing threats to public safety and national security (such as serial murders, kidnappings and bombings).

Myth #2: LE examines the private genetic code of innocent third parties.

LE does not look at the actual private genetic code when using genetic genealogy websites. Investigators only look at a shared percentage of DNA between people – determining how much a suspect’s single nucleotide polymorphism (SNP profile) has in common with a third-party SNP. Busch compared this to having the suspect’s phone number and using a direct-to-consumer database to find out if any of the phone numbers in the database share commonalities with the suspect’s. Law enforcement never sees the full phone number of the third party, they are just told what percentage of the numbers match. On these ancestry services, this is shared in the form of centimorgans, which tell investigators how distant or closely related someone is to someone else.

Myth #3: LE has special access to public databases.

A common sentiment is that law enforcement gets some sort of special access or backdoor keys to ancestry websites, or that the information they get is somehow different from what the average consumer can pay to access it. But the fact is, police investigators access these databases and see the same things about direct-to-consumer services as the public, according to Busch.

Myth #4: The technique will lead to wrongful convictions.

As the willingness to use this investigative technique in cold case stacks grows in agencies across the country, one of the biggest public fears is that using the FGG will lead to wrongful convictions.

Busch explained that going through the technique used by law enforcement investigators makes it impossible to catch the “wrong” guy. As stated by Busch, the process of using FGG basically consists of:

  • Upload DNA and find people the suspect shares common DNA with
  • Use the proximity of the suspect’s “genetic distance” to these “relatives” to triangulate where the suspect might be
  • Assess the entire circumstance before targeting a suspect
  • Confirm suspect’s DNA matches crime scene DNA before anyone is arrested

The FGG is a tool used as an investigative lead, but not as an arrest mechanism. Probable cause must be established, including the aforementioned comparison of the suspect’s DNA to DNA at the crime scene.

Myth #5: LE’s use of genetic genealogy is “more invasive” than traditional investigation.

The feeling that FGG is somehow more “invasive” than other traditional investigative techniques probably stems from its novelty. Busch pointed to many “standard” techniques, such as surveillance, search warrants and interrogations, to highlight how less invasive FGG is – a process that essentially involves:

  • Put crime scene DNA in a public database
  • See shared DNA percentages
  • Using open source research to triangulate who might be the suspect
  • Collect the suspect’s DNA and confirm the match

For more on Kramer and Busch’s experience with FGG, including working on the Golden State Killer case, access the full webinar here.