The Dark Side of DNA Evidence

The Dark Side of DNA Evidence

Collecting DNA upon arrest can identify the guilty and exonerate the innocent. But it also amounts to an expanding racial dragnet.


A DNA analyst processes evidence. (AP Photo/Marshall University, Alex Wilson)

On February 26, the Supreme Court heard oral arguments in Maryland v. King, which presents the question of whether the Fourth Amendment permits the warrantless collection of DNA from people arrested for, but not convicted of, a crime. Currently, twenty-eight states and federal law enforcement collect DNA upon arrest—when a person is still presumed innocent. During oral arguments, Justice Samuel Alito called it “perhaps the most important criminal procedure case that this Court has heard in decades.” 

The case goes back to April 10, 2009, when Maryland police arrested Alonzo King on assault charges. A DNA sample was collected, and four months later, it was found to match evidence from an unsolved rape, which led to King’s conviction for the crime. The case is precisely the sort of example given by proponents of broad DNA collection: DNA has the power to identify the guilty and exonerate the innocent.  But in King’s case, the Maryland Court of Appeals determined that arrestees have privacy expectations that outweigh the state’s crime-solving interest.

In its petition to the Supreme Court, Maryland argues that collecting DNA is no more invasive than its twentieth-century counterpart, the fingerprint. But King and opposing groups filing friend of the court, or amicus, briefs respond that unlike fingerprints, DNA is a trove of personal, medical and ancestral information. What’s more, DNA solves cases far less frequently than the state suggests. In 2011, Maryland police collected 10,666 DNA samples; only nineteen led to an arrest. The state’s interest is thus not identification but investigation—and the Court has never
permitted suspicionless searches of suspects without a warrant. If it does in King, there will be no principle limiting when our DNA may be collected in the name of fighting crime.

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But beyond privacy concerns, there is another reason to reconsider DNA collection on arrest. Because people of color are disproportionately stopped, searched and arrested, they will disproportionately bear the burden of this genetic dragnet. And because DNA samples can be used to establish family relationships, it has the potential to widen the surveillance to entire communities.

Maryland’s petition argues in favor of further incorporating DNA “into established criminal procedure.” But this is precisely the danger. Many criminal procedures, no matter their original intent, disproportionately affect people of color. An amicus brief filed by Howard University provides three examples: the “war on drugs” and two of its symptoms, the New York Police Department’s “stop-and-frisk” policy, and pretextual traffic stops—in which police seize on minor violations for the chance to investigate “suspicious” drivers.

The latter examples show why putting the power of DNA collection in the hands of police is so risky. “The wider the discretion that law enforcement officers have in implementing policies to serve their crime control ends,” Howard’s brief argues, “the more likely that these policies will be used to harass and infringe upon the rights of people of color.” Maryland’s petition cites the National Research Council on the “objective standards of DNA comparison.” But we should not confuse the objectivity of how samples are tested with the subjectivity of how they are collected. DNA is a value-neutral biological molecule, but DNA databases are mirrors that reflect the bias in justice systems. A cautionary example: by 2008, Britain’s National Database stored DNA from 27 percent of the black population and 77 percent of young black males.

This is already happening here. By 2011, African-Americans made up 40 percent of the Combined DNA Index System (CODIS), according to Jeremy Gruber, executive director of the Council for Responsible Genetics. Established by the DNA Identification Act in 1994, CODIS is used by the FBI to store and search DNA profiles collected by federal, state and local law enforcement. When exact matches cannot be found for an unknown sample, many states resort to partial matches, using different markers to track down potential family members.

Because African-Americans are significantly overrepresented in CODIS, it is possible to use the database to identify up to 17 percent of the country’s entire African-American population, researchers at Duke University’s Center for Genome Ethics, Law and Policy found in 2011. Although only four states explicitly permit familial searches, the ACLU has found that nineteen have used a partial match to connect an unknown sample with a potential relative of someone in CODIS—even though fifteen of those states prohibit using the database for this purpose. In California, which permits familial searching, an “initial candidate list” of up to 168 people is created. That list is then narrowed and nonrelatives removed. A potential relative who remains on the list becomes vulnerable to police investigation. This is why Howard University’s brief calls these efforts a “‘probable cause’ generator.”

Once a person is in the database, it can be hard to get out. According to the National Institute of Justice, only nine of the twenty-eight states that collect DNA from arrestees expunge the samples automatically if the person is not convicted. But even in these cases, the procedure is not straightforward. In Maryland, a sample can be expunged only when a charge is filed. What happens if a charge is never filed? In such cases, the Electronic Frontier Foundation points out in its amicus brief, “the arrestee must take the effort to get the sample expunged.” And in some states, such as California and Ohio, there is no right to counsel for expungement proceedings. California arrestees, if not charged, must wait until a statute of limitations expires before they may initiate the expungement process. The ACLU calculates that 19 percent of California felony arrestees in 2011—55,768 people—were never charged with a crime.

The Court is expected to hand down a decision in King before summer. How it will rule is difficult to predict. While it may turn, as usual, on Justice Anthony Kennedy, the alignment may be unusual. When Maryland’s chief deputy attorney general, Katherine Winfree, recited the number of convictions won through DNA matches, Justice Antonin Scalia fired back, “If you conducted a lot of unreasonable searches and seizures, you’d get more convictions, too. That proves absolutely nothing.” On the other hand, Justice Stephen Breyer pushed back against King’s attorney, saying DNA tests are “no more intrusive” than fingerprints but “much more accurate.” 

Forensic DNA collection, as a modern method, reveals old truths about how we criminalize entire populations. In a racially biased system, DNA collection on arrest creates a racial dragnet. But that bias becomes invisible when the data are considered neutral. When one group is overrepresented, whether in statistics or a database, its members become coded as criminals—and clearly in need of additional surveillance. If the Court permits DNA collection upon arrest, law enforcement may solve some crimes, but only as it tracks a wider and wider pool of innocent people.

In our July 2-9, 2012, issue, Nation legal affairs correspondent David Cole inveighed against “The Outrage of Stop-and-Frisk Policing.”


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