Familial Searching Hits The Spotlight

The use of DNA technologies in criminal investigations is expanding at a breakneck pace. One of the most controversial applications is familial searching. When unknown perpetrators leave blood or other biological materials at crime scenes, a profile is created to check against known profiles in forensic databases. Sometimes the unknown profile may not find an exact match, but may be similar enough to point to a family member since relatives share genetic similarities. Familial searching involves leveraging these similarities to expand the scope of DNA databases to implicate persons who would otherwise not be identified.

Despite the controversy behind this approach, familial testing hit the national spotlight this past week with reports that it led to the arrest of a Southern California serial killer known as the ‘Grim Sleeper.’ The New York Times reports:

Lonnie D. Franklin Jr., 57, was charged Thursday with 10 counts of murder and one of attempted murder after the state DNA lab discovered a DNA link between evidence from the old crime scenes and that of Mr. Franklin’s son, Christopher, who was recently convicted of a felony weapons charge.

The information developed from the state’s familial search program suggested that Christopher Franklin was a relative of the source of the DNA from the old crime scenes. The police confirmed the association of Lonnie Franklin through matching of DNA from a discarded pizza slice. The match provided the crucial link in a seemingly unsolvable crime that struck terror and hopelessness throughout one of the city’s poorest areas for years.

Critics have raised concerns about familial searching’s ability to invade innocent people’s privacy and potentially subject them to harassment simply because a relative had a run-in with the law. Moreover, Blacks’ and Latinos’ disproportionate representation in the criminal justice system – linked to their communities’ disproportionate policing and other inequalities – suggests that they will most likely bear the brunt of these problems. Stanford’s Hank Greely and Berkeley’s Erin Murphy discuss some of these ethical issues further in the interview below.

Despite these concerns, Franklin’s arrest is a cause for celebration not only because a serial killer seems to have been taken off the streets, but also because it seems to have been done in a measured and responsible manner. A New York Times editorial notes

Under rules set up by [California] Attorney General Jerry Brown, familial searching cannot be used unless all other investigative leads have been exhausted. The crime must be murder or rape, and the criminal has to be an active threat to public safety — still committing crimes.

A committee of lawyers and forensic experts in the attorney general’s office evaluates all requests to do a familial search and votes on whether to proceed based on those criteria, as well as the strength of the DNA match and several other factors.

This is more than reasonable. However, if the short history of DNA forensics has taught us anything, it’s that limited and measured approaches can give way to aggressive and intrusive campaigns that are anything but limited and measured.

Case in point: DNA databases started as repositories for those convicted of violent crimes like rape and murder. Fast forward a couple of decades, and we now have a proposal that individuals arrested for (not charged or convicted of) any penal offense – felonies and misdemeanors – should have their DNA stored by the State.  So while we can all celebrate what seems to be the Grim Sleeper being brought to justice, it would still be wise to keep an eye on exactly how state and federal governments plan on using this forensic tool in the future.