The “Grim Sleeper” serial killer was caught because California authorities found a partial DNA match with an individual in its database. That meant that the killer was probably related to the owner of that DNA, and indeed he was. We see this approach on the various “C.S.I” shows, but in real life using family DNA to identify a criminal is relatively rare, because only two states, Colorado and California, permit a  “familial search,” the use of DNA samples taken from convicted criminals to track down relatives who may themselves have committed a crime.

Why only two? The science is reliable, and a familial search can narrow the pool of suspects to the point where solving a crime becomes inevitable. Nevertheless, civil libertarians argue that the technique raises privacy concerns. Michael Risher, a lawyer with the American Civil Liberties Union of Northern California, told the New York Times there was the possibility of innocent people being harassed in the pursuit of a crime. “It has the potential to invade the privacy of a lot of people,” he said.

Yes, Michael, it is called “investigation,” and if it helps catch serial killers—or, for that matter, serial robbers, muggers, or arsonists, the intrusion on privacy is minimal, reasonable, and ethical.  Risher is really suggesting that if it is determined that some relative of my mother is a serial killer, I am being unreasonably harassed by investigating officers asking me where I was when the victims were killed, or asked for a cell sample.

I am not. First there is a crime, with unidentified DNA evidence. Next the DNA evidence matches sufficiently with DNA on file that the police know the real criminal is a relative of the owner of the match. Then those in the familial chain are questioned and eliminated, until the perpetrator is found. Should I be angry at law enforcement for “invading my privacy”? No! I should be angry at the my cousin, the criminal, for making my DNA suspicious.

The civil libertarians have another complaint to offer in order to keep a superb crime-solving tool in the closet: racial profiling, sort of. Since a disproportionate number of African-Americans make up the prison population where much of the DNA database originates, this means that more black family members are likely to be investigated than whites. “I can imagine lots of African-American families would think it is not fair to put a disproportionate number of black families under permanent genetic surveillance,” said Jeffrey Rosen, a law professor at George Washington University.

I imagine a lot of criminals are unhappy about this use of DNA too. “Genetic surveillance”? The DNA’s in the system, and examining it for similarities to on-the-scene evidence doesn’t inconvenience the individual whose DNA is on file one bit—unless, of course, he committed the crime. If the African-American familial search doesn’t turn up a match, then there is no harm done. If it does turn up a match that proves a family connection, the family cannot reasonably claim it’s been “profiled.’ There was a match. They members of the family are being investigated not because of their race, but because they have a criminal family member in their midst. If African-Americans want to address this lack of “fairness,” they need to address the causes of the disproportionate number of black criminals and criminals. There is nothing at all unfair about the familial search process. Calling it “racial profiling” is more than a logical stretch; it is dishonest.

I know that our guardians of our civil liberties must be especially vigilant, which sometimes means that they have to sound the alarms when nothing alarming has happened. In this instance, however, their arguments sound more  like hostility to effective law enforcement than advocacy for privacy and civil rights. Of there really is something unethical about familial DNA searches, they haven’t identified it.