True Crime Thursday – DNA Solves Cold Cases


Debbie Burke


Memo to Criminals: If the statute of limitations hasn’t expired, don’t send your DNA to 23andMe.

The combined tools of genealogy and DNA databases are solving old murder cases.

Until recent years, a DNA sample from a crime scene meant little unless it matched an already existing profile in a law enforcement database. But the popularity of DIY home DNA tests adds a new wrinkle.

People seeking their ethnic roots send cheek swabbings to genetic genealogy databases like There, DNA samples are used to build family trees reaching generations back in history.

While you may find it interesting that Mary Queen of Scots or Jesse James is a distant relative, what happens if your DNA also shows you’re related to a criminal?

Most famously, the Golden State Killer was linked to decades of murders and rapes based on DNA information from Parabon Labs.  Parabon claims to have helped solve 30 cold cases. According to their website:

“Genetic genealogy has traditionally been used to discover new relatives and build a full family tree. However, it can also be used to discover the identity of an unknown individual by using DNA to identify relatives and then using genealogy research to build family trees and deduce who the unknown individual could be. These techniques…apply equally as well to forensic applications. Genetic genealogy has been used to identify victims’ remains, as well as suspects, in a number of high-profile cases. Most recently, genetic genealogy was used to zero in on a suspect in the Golden State Killer case.”

Law enforcement can request information from consumer DNA databanks to trace suspects in unsolved crimes. But ethics concerns are on the rise after the founder of GEDmatch allowed access in an assault case in Utah without first informing its customers.

Surveys indicate most people believe consumer DNA databases should be used in cases of violent crimes. But what about offenses like credit card fraud or unpaid child support?

TKZers, have you sent your DNA to a database like 23andMe,, Family Tree, My Heritage, etc.?

Are you concerned about the privacy of your genetic profile?

Where would you draw the line for law enforcement uses? Violent crimes? Non-violent felonies? Misdemeanors?

This entry was posted in DNA results in fiction, Writing and tagged , , , by Debbie Burke. Bookmark the permalink.

About Debbie Burke

Debbie writes the Tawny Lindholm series, Montana thrillers infused with psychological suspense. Her books have won the Kindle Scout contest, the Zebulon Award, and were finalists for the Eric Hoffer Book Award and Her articles received journalism awards in international publications. She is a founding member of Authors of the Flathead and helps to plan the annual Flathead River Writers Conference in Kalispell, Montana. Her greatest joy is mentoring young writers.

16 thoughts on “True Crime Thursday – DNA Solves Cold Cases

  1. I send my DNA to 23andMe and it’s really very interesting. I also did my rescue dog’s DNA to find out what breeds he is. The rescue organization said he was a Great Dane/pit bull mix. His DNA came back approximately 50% Doberman, 20% boxer, 20% Newfie, and less than 10% pit bull. His DNA was important to me because his breed impacts his personality and I was afraid I was adopting a short-lived Great Dane.
    As to crime, I think if you share your DNA with a database that law enforcement should have access to it to find felony criminals. I don’t want law enforcement finding me to be a match to a third cousin that has run up $20K in parking tickets. If for no other reason than I don’t even know my third cousins. 23andMe has like 1,100 relatives listed for me. After my mother and brother, the next relative drops to my second cousin and we share just 3.51% DNA. So after the top 3 of my “1100 relatives”, I share less than 3% DNA with any of them. At that point, it has to be like looking for a needle in a haystack.

    • Fun facts about your dog, Alex.

      Sharing DNA with a commercial database seems similar to sharing photos and personal information on social media. You give up certain expectations of privacy.

    • I’m imagining the future, Marilynn, although credit card fraud was not the best example to use.

      At this point, the cost and time involved with genetic genealogy are probably too great unless the crime is serious like murder, rape, etc. But new breakthroughs get faster and cheaper at a dizzying rate. I’m guessing in coming years, such tracking could be used to locate suspects for lesser crimes, like burglary, vandalism, etc.

      For instance, ten years ago, testing a dog’s DNA would have been prohibitively expensive. Now, pet owners do it all the time, as Alex did.

  2. My wife, one of her brothers, and my two children all sent swabs to 23andme. My wife and her brothers were adopted. My BIL’s biological father “spread the wealth”. He has met two or three of his half sisters. They think there may be as many as a dozen “halfs” out there.

    Using private company DNA samples lead down a whole bunch of technical/chain of custody issues. It will be interesting to see where it all comes out. For those of you who write techno-thrillers, if I want to pin a rape on the congressman, all I need is his DNA on the panties and then a hack at 23andme. You take it from there. I am guessing some of the testing sights don’t have NSA level computer security.

  3. Even without DNA, the finger can be pointed at you. One of the pictures in the paper from the South Side Rapist looked a lot like me.

    There was another serial rapist working my neighborhood in the 1980’s-90’s. The description the victims gave was “powerfully built black man, 20-25 years old, shaved head.” It matched one of my pizza co-workers. He was pulled over two or three times a day. When the actual rapist was caught, 45-50 years old with a gray beard, he looked nothing like my buddy.

  4. My concern is that one day they DNA companies could share your family’s DNA information with potential health insurance or life insurance companies. Then they could use the information to deny or hike prices based on your DNA results.

    At the same time, knowing you have a gene that could lead to a major medical problem in the future could give you and your doctor the information and time to make better choices to mitigate or protect you from future medical possibilities.

    Like most things in life, things are seldom all good or all bad.
    Great post, Deb. Gets the ole brain cells to start some critical thinking,

    • Deb, you’ve brought up more intriguing ideas for plots. Greedy, unscrupulous people will find a way to profit from sensitive DNA info and cause unsuspecting people to suffer. That’s a crime, even if it’s not against the law. It makes rich fodder for the fiction writer.

  5. I cannot for the life of me fathom why anybody would give all the personal information that is them and just give it away, pay actually, when that company can and will sell it to whoever they please. You have no control over what happens to it, whether it goes to law enforcement, an insurance company, a prospective mate, a vindictive ex, or some company that wants to market some product to you based on your genetics. That’s just insane.

  6. Interesting topic. I have not done any DNA tests, nor do I plan to. Don’t have a reason. I know my family history back to great, great, great grandparents, and that’s far enough.

    Every day my husband (retired law enforcement) tells me of another cold case solved with DNA. It’s good to catch these criminals, but I figured they were getting the samples during a legal process, never thought of the private companies.

    Always a mix of good and bad. Let’s hope the bad never overwhelms the good.

    • Cecilia, I’m all for catching criminals, esp. rapes and murders that happened before DNA was available. But I do have privacy concerns. You’re right about the mix of good and bad–there’s always the potential for misuse or abuse of data.

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