Feb 21 5:00 PM

DNA collection aids arrests—but what about privacy?

In this week’s episode of “TechKnow,” we highlight the latest advances in forensic technology that are helping law enforcement agencies identify suspects and solve crimes with increasing accuracy. Cases that were left cold for years are being revisited with fresh eyes—and, more importantly, fresh technology. Where we have seen some of the largest leaps in the past decade is in the analysis of contact trace DNA or “Touch DNA.” A person sheds about 400,000 skin cells per day, and with smaller and smaller samples required to make an accurate match, it is becoming more difficult to commit a truly untraceable crime.

But in order to match crimes up with criminals based on trace amounts of DNA, it also requires expanding and centralizing local, state, and national DNA databases used by law enforcement.

Last June, the Supreme Court ruled 5-4 that it was constitutional to take DNA swabs from people who have been arrested for “serious crimes” without getting a warrant or waiting for a conviction. These DNA samples can be added to a database and can be used to solve past crimes—and also future crimes.

Laws in 28 states already allow for such samples to be collected upon arrest for felonies (and sometimes misdemeanors), and it’s likely that many if not all of the other 22 states will pass similar laws in light of the Supreme Court decision.

Privacy advocates warn that warrantless searches of a person’s DNA, especially for misdemeanor arrests, is a slippery slope.

Even conservative Justice Antonin Scalia agrees, writing in his Maryland vs. King dissent:

“Solving unsolved crimes is a noble objective, but it occupies a lower place in the American pantheon of noble objectives than the protection of our people from suspicionless law-enforcement searches.”

DNA collection and analysis has become an effective but controversial method of investigating crimes.


Those in favor of including the DNA swab as part of the routine booking process argue that it is no different than fingerprints. While biometric techniques such as fingerprinting have been used in law enforcement since the early 1900s, the systematic collection of biometrics has always been controversial.

Where DNA databases differ from fingerprint databases is in the amount potential information that could be extracted from the samples held—in the future. At the moment, the DNA swab sample doesn’t capture anywhere near all of the 3 billion markers that exist in an entire DNA strand. The sample is limited to 13 isolated markers that proponents say provide no useful information on an individual until a match is made.

However, once these markers are entered into the CODIS database, the national Combined DNA Index System run by the FBI, many police departments do not destroy the sample—they hold onto it indefinitely so that a retest can be done, should there be a positive match. This has privacy advocates concerned that as DNA technology continues to advance, these samples could be revisited and a more robust genetic profile extracted from the full genome.

Even though it is extremely speculative at this point, the concern is that in the future, as technology advances and our ability to access data from the full genome improves, genetic information such as what you look like and where you come from could be used not only in investigations, but also for profiling and predicting crimes. That opens up a Pandora’s box of questions—including whether our legal system is equipped to deal with complex issues of biomedical ethics and genetic privacy.

An investigative technique that is actually already being practiced by a handful of states —California, Colorado, Virgina and Texas—is the familial search. Partial DNA matches reveal possible relatives of a suspect, which can lead to their involvement in investigations. As unconvicted arrestees are added to these widening databases, will familial searches also be allowed in the states where this practice is legal? If so, more and more people, will be entangled in investigations without warrant.

The ACLU says:

“DNA testing of arrestees has little to do with identification and everything to do with solving unresolved crimes. While no one disputes the importance of that interest, the Fourth Amendment has long been understood to mean that the police cannot search for evidence of a crime.”

If a DNA swab is really intended to solve crime, not just to establish a new form of identification, it’s much harder to justify as the morally sound choice, especially when taking into account the presumption of innocence.

False arrests are damaging enough, but to be added indefinitely to a DNA database, without charge, seems more clearly an erosion of an innocent person’s right to privacy. Plus, racial minorities are convicted at a much higher rate than the overall population, according to the ACLU, 65 of prisoners who are sentenced to life without parole for nonviolent offenses are black. Similarly, black inmates make up 45 percent of the state and federal prison population while only 13 percent of the US population is black. These disparities inevitably lead to people of color being subjected to the seizure of their DNA more often than others.

And a recent FBI audit of the national DNA database yielded an unprecedented result: potential errors in nearly 170 profiles were detected. When compared against the 13 million profiles contained in the database, 170 may not seem like a lot, but it calls into question the fallibility of the process. It is also important to note that local and state databases are not subject to the same scrutiny and audits as federal records.

Mandatory genetic collection—like in the sci-fi movie “Gattaca”—may be more equitable, but it isn’t a particularly attractive alternative to privacy advocates, either.

The common argument is that if you are doing nothing wrong, then you have nothing to worry about. Though we’re always excited about innovative technology that can advance—and improve—important work being done, it’s important to continue raising these questions about the scope and future use of DNA evidence.


Learn more about touch DNA analysis and other forensics innovations on Sunday's "TechKnow," 7:30ET/4:30PT.


Crime, Police, Privacy

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