Police in two states are increasingly using a DNA crime-solving technique that some legal experts say amounts to guilt by association: If your brother, father, uncle, or son has been in trouble with the law and is in a DNA database because of it, you, too, could fall under suspicion, reports the Associated Press. The technique is a “familial DNA” search. In what is believed to be a precedent-setting case, Denver police used it to help catch the burglar who left a drop of blood on a passenger seat when he broke a car window and stole $1.40 in change. A growing number of law enforcement agencies nationwide are considering whether to adopt the technique.
“How can we look a rape victim in the face and say, ‘We could have prevented your rape if we had looked at this evidence?'” said Harvard medical school Prof. Fredrick Bieber, who co-wrote a paper suggesting familial DNA searches could solve up to 40 percent more crimes in which DNA evidence is present. A familial DNA search involves looking through a database for a near-match – a close male relative of the perpetrator. Police can then use that information to zero in on whoever committed the crime. The legality of such searches has not been tested in court. Critics complain the technique could subject innocent people to arrest or hours of interrogation. “It makes absolutely no sense,” said University of California-Berkeley law Prof. Erin Murphy. “Other than the misfortune of having a relative that has gotten in trouble, there’s no distinction in their likelihood of having committed a crime.”