The use of overlapping DNA to catch criminals

FamilyTreeDNA, an at home consumer genetic testing company similar to 23andMe and Ancestry.com, has been sharing DNA data with the FBI.  The FBI uses this information in its investigation of violent crimes and/or cold cases.  Reading this article by Matthew Haag in the NY Times made me think a good friend of mine from college.  In the summer of 1997, she was attacked, tied up, and raped by a stranger in her Chico, CA apartment.  When her assailant left the room, she broke free of the restraints and grabbed a pair of scissors.  When he returned to the room, she stabbed him in the arm.  The blood he left on a pillow case provided investigators with the evidence they would use over twenty years later to identify him as Roy Charles Waller, the so-called "NorCal Rapist."

Investigators entered his DNA into the GEDMatch website, which provided them with a list of his close DNA relatives.  That information quickly led them to Waller.  Waller sexually assaulted and/or attacked at least seven victims across six Northern California counties over a 15-year period (1991-2006).  

The investigative tools these type of websites provide to law enforcement and to victims is substantial:

More than 15 million people have submitted their DNA to companies like FamilyTreeDNA in recent years. While they represent a small fraction of all people, the pool of profiles is large enough to allow 60 percent of white Americans -- the primary users of DNA sites in the United States -- to be identified through the databases, according to researchers.

As the number of tests expands in the coming years, researchers believe that 90 percent of Americans of European descent will be identifiable, even if they did not submit their own DNA, according to researchers.

90%!

My friend's whole life changed in an instant that summer.  She waited over twenty years to confront the man who attacked her.  If not for the information that Waller's DNA relatives voluntarily entered into an online genetic testing database, Waller may have never been identified as the NorCal Rapist.  Or the identities of these two murder victims whose bodies were discovered twenty years ago may have remained unknown. 

The use of overlapping DNA to catch criminals curated from Crime and Consequences Blog