You're under arrest (and so is your DNA): the government is collecting DNA from people who've been arrested, but are still legally innocent. Does that violate their privacy--and the fourth amendment?

• Author: Moore, Solomon
• Position: NATIONAL

Brian Roberts, 29, was awaiting trial in March for possession of an illegal drug. At the Twin Towers Correctional Facility in Los Angeles, a sheriff's deputy swabbed the inside of his cheek to collect a DNA sample. The DNA was then translated into a numeric sequence in the F.B.I.'s database of nearly 7 million genetic profiles.

Every Monday from now on, the F.B.I.'s system--housed in a closet-size room at its laboratory in Quantico, Virginia--will search for matches between Roberts's DNA and other profiles from all over the country--in the event that one day, perhaps decades from now, Roberts might leave his DNA at a crime scene.

[ILLUSTRATION OMITTED]

Until now, the federal government genetically tracked only convicts. But in April, the Federal Bureau of Investigation, which maintains the world's largest genetic database, began collecting DNA samples from those awaiting trial and from detained immigrants. The F.B.I. plans to expand the growth rate of its database from 80,000 new entries a year to 1.2 million by 2012--a 15-fold increase.

"We went from federal offenders to arrestees and detained non-U.S, citizens," says Robert Fram, the special agent in charge of the F.B.I. laboratory division. "We don't know where, or if, the number of profiles will plateau."

A GENETIC-SURVEILLANCE SOCIETY?

And the F.B.I. isn't alone: This year, California began taking DNA upon arrest and expects to nearly double the growth rate of its database to 390,000 profiles a year. In all, 15 states have expanded mandatory DNA collection to people who have been arrested or detained but not yet convicted. This move raises concerns about the privacy of people who are supposed to be presumed innocent.

DNA analysis is used in only 10 percent of criminal cases, but it is far more accurate than other techniques; scientists estimate the possibility of a random match at one in a quadrillion (one thousand million million).

Law-enforcement officials say that expanding the nation's DNA database to include legally innocent people will not only help solve more violent crimes, but may also lead to more exonerations: So far, more than 200 wrongfully convicted people have been freed based on DNA evidence.

[ILLUSTRATION OMITTED]

But criminal-justice experts worry that the nation is becoming a genetic-surveillance society and say that in some cases, compulsory DNA collection may violate the Fourth Amendment, which states that "The right of the people to be secure in their persons...