Police believe that they have nabbed the notorious “Golden State Killer,” a man who committed a series of rapes and murders in California in the 1970s and ’80s. Their suspect is former police officer Joseph James DeAngelo, age 72, who has lived for many years in Sacramento. DNA evidence played the main role in identifying him.

Investigators retained DNA evidence from the Golden State Killer’s crime scenes, but they were not able to match it to any of the convicts’ and arrestees’ DNA profiles stored in the FBI’s Combined DNA Index System. As a workaround, police decided to take advantage of the fact the millions of Americans (including me!) have had their genetic information tested by various commercial companies, often as part of their personal genealogical research.

The main commerical companies all claim that they will not surrender their clients’ DNA test results to the police without a proper warrant. So should regular citizens be concerned about how the cops used DNA here?