Genetic Genealogy: Getting Ahead of the Curve.

• Author: Porter, Bryan L.

One common misconception about prosecutors is we are keen to advise law enforcement officers to push the boundaries of established constitutional limits on criminal investigations. My experience has been exactly the opposite: my colleagues respect the Constitution, honor the rule of law, and strongly feel that investigators must stay within established constitutional norms.

As I frequently tell citizens at my office's public events, I am not the enemy of civil liberties. To the contrary, I spend a significant amount of time upholding those liberties, teaching detectives the constitutional constraints on their investigations, emphasizing the judicial preference for searches conducted pursuant to a warrant, and dismissing cases where my legal analysis convinces me evidence was obtained in derogation of the Fourth and Fifth Amendments.

When it comes to assessing the legality of time-tested investigative methods such as interviews and obtaining search warrants of homes, established precedent often provides clear legal guidance. However, where new technology leads to novel investigative techniques, precedent is at best lacking and is often wholly absent. In the absence of binding precedent, I suggest elected prosecutors "get ahead of the curve" and work with investigative agencies to come up with clear guidelines that reach an accommodation between protecting a citizen's rights while still allowing law enforcement the ability to investigate serious crimes.

A great example of an area in which prosecutors should act proactively to set investigative guidelines is the field of forensic genetic genealogy (FGG). (1) Early in 2018, my hometown police department, in conjunction with my office, used FGG to identify, arrest, and successfully prosecute an armed rapist who selected female lifeguards at local pools as his victims. Without FGG, this violent predator would never have been unidentified and would have remained free to strike again. On the strength of FGG evidence, however, he elected to plead guilty and is currently awaiting sentencing.

Since this was the first successful use of FGG in my jurisdiction, the case received a great deal of both media and public attention. As I heard from interested parties, a common theme emerged from their comments. In effect, people were pleased that FGG was used to track down a violent rapist but were concerned that the technique would be used in a panoply of lesser offenses. It was clear that neither the...