The federal government has announced it will expand its  current practice of collecting DNA samples from people convicted of federal crimes and begin collecting them from all people arrested in connection with a federal crime along with many immigrants detained by federal authorities.

This practice is expected to add genetic identifiers from about 1 million people a year to the rapidly growing federal law enforcement DNA database, which now has about 5.9 million people in it.

Thirteen states already collect or are planning to collect DNA samples from everybody arrested, including people never prosecuted, for whom charges are later dropped, and those acquitted. These states routinely forward the data to the national database.

Advocates of this database assure us its only impact will be to make it easier to catch criminals or prevent crime. It is already routine to take fingerprints from anybody who is arrested and the practice doesn’t lead to gross violations of privacy, say some. What’s the big deal about taking DNA, a more precise and reliable identifier?

It is true that DNA is more precise than other forms of identification, and it is also true that DNA technology has been used to prove the innocence of some people. But it’s not difficult to imagine potential problems.

Since the regulations governing this program have not been published yet, there’s time to consider some safeguards.

It would certainly be a problem, of course, if those who have been arrested but did not commit a crime are lumped in with convicted felons and could become targets in investigations of future crimes. In Virginia, one of the first states to adopt a DNA arrestee program, 51 percent of those arrested were eventually dropped from the database because they were never convicted. The preliminary federal rules call for eliminating people never convicted, but only if they petition for expungement. It would be better if expungement were automatic.

Jim Harper, director of information policy studies at the libertarian Cato Institute, pointed out that information stored digitally is different from fingerprints on paper. Digital information can be more easily copied and accessed, which could create the temptation for future abuse.
“A fingerprint on a piece of paper in the basement is still there if the person comes to law enforcement attention again,” he said. “A database is more available, for people who are just snoopy, or possibly for more nefarious reasons,” like harassment or blackmail.

In addition, DNA has information about genetic characteristics, susceptibility to disease and the like. Current FBI rules preclude using samples to study genetic traits, but those rules could be changed or broken. It might be wise to retain only those alleles necessary for identification and destroy the rest, along with the actual sample.

Like any scientific advance, DNA technology can be used well or poorly. Careful consideration now can preserve its value for fighting crime while minimizing the potential for violating privacy.