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Forget Fingerprints: Law Enforcement DNA Databases Poised To Expand

After a U.S. Supreme Court ruling, DNA databases are set to expand. How will the decision affect your privacy?

ByValerie RossNOVA NextNOVA Next
Certain information encoded in DNA, seen here in an x-ray data visualization, is being increasingly collected and stored by law enforcement organizations.

In June, the Supreme Court ruled that it is constitutional to take DNA samples from people who have been arrested for serious crimes—without a warrant, much less a conviction. Like bits of DNA taken from people found guilty, those samples can be entered into a database and used not only for the case at hand, but compared to other crime scene samples, connecting the arrestee to past crimes.

The case before the Supreme Court focused on Alonzo Jay King, Jr., who was arrested for assault in Wicomico County, Maryland, in 2009 after pointing a gun at several people. Although the police didn’t need DNA to link King to the crime—they had eyewitness testimony, and King himself admitted what he’d done—they took a cheek swab. Maryland law says that people merely arrested—not yet convicted—of a violent crime can have their DNA taken and entered into the national database. King’s DNA then linked him to an unsolved 2003 rape, for which he was found guilty. King and his lawyers challenged that conviction on the basis that the DNA sample was an unreasonable search.

The Supreme Court upheld Maryland’s law—narrowly, five to four. Five of the justices, led by Justice Anthony Kennedy, said that taking DNA from arrestees was a “reasonable search” with a large public safety payoff, comparable to fingerprinting for identification. Four disagreed, with a blistering dissent by Justice Antonin Scalia saying that the decision violated Fourth Amendment rights; Scalia wrote, “Make no mistake about it: As an entirely predictable consequence of today’s decision, your DNA can be taken and entered into a national DNA database if you are ever arrested, rightly or wrongly, and for whatever reason.”

Depending on whom you ask, DNA databases herald a future of either lower crime or less privacy.

Today, 28 states and the federal government already collect genetic samples from people arrested for serious crimes (mostly felonies, though some jurisdictions include certain misdemeanors as well), while the remaining 22 states only take samples from people convicted of those crimes. The recent ruling is likely to have wide-reaching implications—both for states that already have databases and for those that don’t, yet.

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Depending on whom you ask, DNA databases herald a future of either lower crime or less privacy. Many of the arguments echo the Supreme Court ruling and dissent: Proponents say the databases help police catch dangerous criminals faster and identify offenders who had eluded detection, thus providing a big pay-off for each law enforcement dollar. Others object to the databases on the grounds that they violate privacy by storing genetic data, are an inefficient use of limited resources, or are likely to encompass more and more people—perhaps including those never even suspected of a crime.

DNA databases have been expanding, and rapidly improving technology is poised to generate more detailed profiles more quickly. The question now is what the future will look like, particularly in the wake of the Court’s decision.

What DNA Samples Reveal

DNA databases help catch criminals, supporters say. And not just any criminals: because the majority of genetic evidence is collected in homicide and rape cases, the databases are particularly useful in identifying people who have committed violent crimes.

To get a DNA sample—whether from an arrestee or a convicted criminal—law enforcement officers swab the inside of a suspect’s cheek. They then send the swab, now coated in DNA, to one of more than 200 public and private labs that analyze samples for the Federal Bureau of Investigation’s Combined DNA Index System (CODIS), which catalogs these genetic profiles at the local, state, and national level. The labs don’t read the full genome of each convict’s or arrestee’s DNA; in fact, they don’t analyze any actual genes to include in the database, none of the stretches of DNA that code for health risks or visible traits. They look at 13 locations, called loci, on each of two sets of chromosomes in what’s commonly called “junk DNA,” or bits of the chromosome that don’t code for anything in particular. Each DNA profile is made up of 26 data points.

Law enforcement organizations typically collect DNA from arrestees using cheek swabs.

Since DNA profiles can be prepared quickly and their data can be stored indefinitely, DNA databases can pinpoint the perpetrator of recent or ongoing crimes as well as help solve decades-old cold cases. Taking DNA at arrest also prevents future crimes, proponents say, by linking repeat offenders to past crimes and thus taking them off the street.

The Supreme Court’s recent ruling “was an excellent opinion and it was an important case for public safety given the public safety benefits of arrestee databases,” says California deputy attorney general Enid Camps, who frequently handles the state’s DNA cases. Taking DNA samples from arrestees, she says, is “more important than taking samples after they’ve been convicted, because it helps put objective science earlier in the criminal justice system, not just at the end.”

Like a Fingerprint…or Not

One of the primary concerns with adding arrestees to DNA databases is how much information the samples could reveal. Proponents say the profiles are similar to mug shots and fingerprinting. In fact, the technique is often called “genetic fingerprinting.” In terms of how much information they divulge about a person, “they’re effectively just like a fingerprint,” says John Butler, a forensic genetics researcher at the National Institute for Standards and Technology. They’re sufficiently different from person to person, but they don’t tell you what that person looks like or where they’re from.

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But unlike fingerprints, DNA is inherited in a far more consistent way. It shows who’s related to whom—something a standard fingerprint could never reveal. California, Colorado, Virgina, and Texas are using that to their advantage, employing a technique called familial search. Law enforcement agencies turn to familial search when a crime scene sample only contains a partial match. That partial match may point investigators to that person’s father, brother, son, or another close relative, giving them new leads where there otherwise may be none. (Most familial searches use data points on the Y chromosome, which only men have.)

The Supreme Court ruling noted that Maryland’s law forbids familial search, though that particular part of the law hasn’t been tested yet. Still, the technique has been used in recent high-profile cases, such as the Boston Strangler and Grim Sleeper murders. As databases expand to include more arrestees, familial search will become a more pressing issue.

Life of a Sample

Even if the profile itself reveals relatively little information, many people are concerned that most jurisdictions keep an individual’s sample—which contains their full genome and all the personal information it could reveal—after their profile has been entered into the database. If a person is exonerated, they can have their profile deleted and their sample discarded, though the process can be difficult. Most labs keep the samples reportedly for the purpose of quality assurance testing in case of a match, says John Butler, a forensic genetics researcher at the National Institute for Standards and Technology: If an individual profile matches a crime scene profile, the sample will be retested to make sure the match is correct.

Retaining samples also allow the labs to update their technology. When DNA profiling switched over to the current method, labs retyped old, stored samples to create a more modern database. Such a switchover may happen again soon: a working group formed by the FBI recommended that CODIS begin testing additional loci , upping the number from 13 to 20 to reduce the likelihood of false positives. Existing samples will have to be retested. Keeping samples also provides databases with updated profiles of people who might have passed away, been paroled, or who would simply take precious law enforcement resources to track down, Butler points out.

The FBI is a major force behind the expansion of DNA databases.

That doesn’t sit well with Michael Risher, an attorney at the ACLU of Northern California. “The government insists not just on keeping DNA profiles they’ve developed, but on keeping the sample indefinitely,” he says. “There’s no question that our DNA contains a huge amount of info about us and that science is learning to access that info more and more every passing year.”

California deputy attorney general Michael Chamberlain argues that keeping the full sample ensures quality, saying it helps make the databases more effective and prevent potential false hits. In terms of privacy, “people say the state has all this personal information, but we do not process it,” he says. “I’d hope the ACLU would come into court if we looked at personal genetic information, but that’s never happened, and cannot happen under the law.”

While the government is limited by law to conducting only those tests needed to obtain a profile, laws can change, Risher says, and government officials can violate laws that exist. If the government doesn’t need our full genetic information, he says, why should they keep it? Risher views DNA as another piece of personal information, like emails. “We don’t think government officials can come collect every email we ever sent and say, ‘No worries, we’re not going to read these emails unless we get a court order.’”

Expanding Scope

With more than half the states taking samples from arrestees, DNA databases have grown rapidly. At the national level, CODIS has more than 10.1 million offender DNA profiles and 1.3 million arrestee DNA profiles as of January 2013. Together, that’s over 3.5% of the U.S. population. According to the FBI’s website, the network “has produced over 200,300 hits assisting in more than 192,400 investigations” as of January 2013.

At this point, the only thing that’s limiting the expansion of DNA databases is the fact that samples often come in faster than labs can analyze them. That’s produced enormous backlogs. To address the problem, the federal government has given $151 million annually to state and local governments since 2005 to process DNA samples. That assistance has been extended through 2014 . But even that funding hasn’t let labs catch up. “There’s been an effort to reduce backlogs, but there have been more samples to put into the system,” Butler says.

“If you’re arrested for having a dog off a leash in a federal park, you have to give a sample.”

As of now, the federal government and slightly more than half the states bank DNA from arrestees. But it’s likely that many more states will start doing so in the coming years. Part of the reason for that is the Supreme Court ruling, which has removed some of the legal uncertainty around including arrestees in DNA databases. The other is that, as of January, Congressional legislation kicked in that will provide federal funding for states to put towards arrestee DNA databases.

“There’s the decision finding it constitutional, and also there’s funding for states that don’t have it,” says Camps, the California deputy attorney general. The Supreme Court ruling combined with the Congressional promise of financial support, she thinks, “will make it a lot more likely that more states will develop this kind of database, which has really been of great importance in states like California.”

Risher, the ACLU attorney, also predicts that DNA databases are likely to continue their expansion. But unlike Camps, he doesn’t feel that the expansion will necessarily benefit society. Sampling laws were signed to target violent criminals, but they have already expanded in scope. “If you’re arrested for having a dog off a leash in a federal park, you have to give a sample,” he says.

David Kaye, a Penn State law professor who’s an expert on scientific and forensic evidence, also predicts that, in the long run, DNA sampling “will be much more like fingerprinting in the sense of being done across a wider range of crimes,” he says. “That’s what happened with convicted offenders: It started out with just sex offenses and murder, then moved to violent felonies, then in some states to all felonies and certain misdemeanors.”

In addition to hashing out for which crimes arrestees’ DNA should be taken, Kaye says, there are other questions that will have to be addressed as more states implement their own databases: How early in the process should DNA be taken and sequenced? In states where familial searching is used, will it be allowed in arrestee databases as well? And if—or, more likely, when—technology advances to the point where DNA sequencers, like breathalyzers, can provide rapid analysis on-scene, how will that change things?

“We’re past the starting gate,” says Kaye, “The question is, how far to run with this.”

Image credits: Kenneth Eward, BioGrafx Scientific & Medical Images, Ovid, Michigan/NSF, netdoktorde/Flickr (CC BY-NC 2.0) , nostri-imago (CC BY 2.0)

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