Guilt By Association: Using Familial DNA to Finger Criminals

The Washington Post has a good article about how DNA from a suspect's family members can be used to find out if he or she may have committed a crime.

The BTK murderer in Kansas was identified using DNA from a pap smear that his daughter had when she was in college. The police checked her DNA against DNA collected from the crime scenes and it was a close match. With this evidence, the police got a warrant requiring the suspect to submit to DNA testing and it matched perfectly. The murderer is now serving ten consecutive life sentences.

As the article points out, such familial DNA searching causes unease among civil libertarians. To wit:

"If practiced routinely, we would be subjecting hundreds of thousands of innocent people who happen to be relatives of individuals in the FBI database to lifelong genetic surveillance," said Tania Simoncelli, science adviser to the American Civil Liberties Union….

The Supreme Court has repeatedly held that authorities may not conduct searches for general law enforcement purposes without suspicion about individuals. Although convicted criminals have a diminished expectation of privacy, searching a database for unknown relatives might violate that principle, said Jeffrey Rosen, a George Washington University law professor.

"The idea of holding people responsible for who they are rather than what they've done could challenge deep American principles of privacy and equality," he said. "Although the legal issues aren't clear, the moral ones are vexing." …

Stanford University law professor Henry T. Greely estimates that at least 40 percent of the FBI database is African American, though they make up only 13 percent of the U.S. population. That is because in an average year, more than 40 percent of people convicted of felonies in the United States are African American, he said.

If the national database were used for familial searching, he said, and assuming that on average each person whose profile in the database has five first-degree relatives, authorities would be "putting under surveillance" roughly a third of the African American population, compared with about 7.5 percent of the European American population, he said.

"I don't think anybody's going to be falsely convicted," he said. "It's the time, hassle and indignity of being interviewed by the police. How much is that worth? How much does that cost a person? I don't know, but it's not zero."

Do you have a right to withhold your DNA from government databases? And is the risk of an extra bit of hassling of the innocent worth finding and convicting criminals? In an earlier column I predicted:

Kinship DNA searching is thought to be different from using fingerprints because fingerprinting can generally incriminate only one person (though similar fingerprint patterns can sometimes point to a relative as a criminal perpetrator). DNA kinship searching necessarily implicates both guilty and innocent blood relatives of the person whose profile is in the databases. As Harvard researchers Frederick R. Bieber and David Lazer note, "Genetic surveillance would thus shift from the individual to the family."

DNA kinship searching will not solve every crime because in order for it to work, the DNA profile of a close relative must already be on file. Interestingly, it turns out that according to a 1999 Bureau of Justice survey, 46 percent of prison inmates had at least one sibling, parent or child who had been incarcerated at some point. This sad fact increases the chances that DNA kinship searching will turn up a suspect. Of course, if you happen to be the good kid in a family of crooks you will be understandably annoyed by a police "request" for your DNA, but, on the other hand, it would be silly for the cops to ignore clues from kinship DNA searches.

One suggestion for avoiding DNA kinship searches which casts suspicion on guilty and innocent family members alike would simply be to require that every American have his or her DNA profile in a database. The idea is that law enforcement officials could simply check whatever DNA samples they obtain from a crime scene with the directory for a perfect match. The FBI already has a computerized database of 250 million sets of fingerprints representing 74 million people. I predict that since collecting DNA is no more invasive than fingerprinting, it seems very likely that a similarly sized national DNA database will be created in the near future.

Whole Post article here. How concerned should we be by the growth of government DNA databases?