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April 8, 2007

Near-miss DNA Searching

"Familial searching" is back in the news.  60 Minutes had a segment on it last week called "A Not So Perfect Match: How Near-DNA Matches Can Incriminate Relatives Of Criminals," and the LA Times ran an editorial by UCLA Professor Jennifer Mnookin entitled "The Problem with Expanding DNA Searches: They Could Locate Not Just Convicted Criminals But Also Relatives -- Violating Privacy."

The phrase "familial searching" is slightly misleading. As Mnookin notes, when a DNA sample from a crime scene is almost -- but not quite -- a match to a particular individual in the convicted-offender database, it could well come from a full sibling or a parent or child. As one moves farther out on the family tree, however, it is difficult to distinguish relatives from unrelated individuals with the DNA types listed in the database.

Although one cannot expect too much from short editorials and TV clips, it may be worth noting and commenting on some of the arguments against near-miss searching floated in these media. The major argument offered on the 60 Minutes show was that looking for leads to relatives is "genetic surveillance." Of course, this is more of a slogan than an argument. Calling the practice "genetic" or "surveillance" does not make it wrong. People would prefer not to come to the attention of the authorities, but what is the underlying right that following these leads violates? Or is the argument not about rights, but policy? Is the unarticulated premise that the police should not have a way of tracking the whereabouts of large numbers of people who are not (yet) known to have done anything wrong? Perhaps, but don't people become suspects for all kinds of reasons beyond their control all the time?

Professor Mnookin formulates the point somewhat differently when she writes that “[p]ut plainly, it is discriminatory. If I have the bad luck to have a close relative who has been convicted of a violent crime, authorities could find me using familial search techniques. If my neighbor, who has the good fortune to lack felonious relatives, left a biological sample at a crime scene, the DNA database would not offer any information that could lead to her.” The “discrimination” here is that people whose parents, children, or siblings are convicted criminals can be caught. But why is this under-inclusiveness such a serious concern? By this logic, wouldn't it be equally discriminatory to seek or follow up on leads by interrogating friends of a criminal? To paraphrase the editorial, “If I have the bad luck to have a friend who is willing to talk to the police, authorities could find me using interrogation techniques. If my neighbor, who has the good fortune to lack loose-lipped friends, committed the same crime, the interrogation would not offer any information that could lead to her.” “Discrimination” that arises from “bad luck” is not generally a concern. Something else must be doing the work here.

Another less-than-obvious claim cast in terms of "discrimination" or "fairness" is that “those people who just happen to be related to criminals have not given up their privacy rights as a consequence of their actions. To use a search technique that targets them simply because of who their relatives are is simply not fair.” But it is not apparent that there is any fundamental “privacy right” to be free from becoming the target of an investigation because of one’s associations with individuals who come to the attention of the police. Suppose that I commit a crime all by myself but I have a nosy neighbor who shadowed me. He gets caught committing a totally unrelated crime, and he bargains for a lower sentence by offering to rat on me. Would we say that “those people like me, who just happen to be living next to nosy criminals have not given up their privacy rights as a consequence of their actions. To use a search technique that targets them simply because of who their neighbors are is simply not fair.”?

A more troubling point is that near-miss searching will have a disparate racial and economic impact because racial minorities and less affluent individuals are overrepresented among convicted offenders. Is the disparate impact is acceptable for the convicts but not for their closest relatives? Mnookin points out that in upholding the constitutionality of convicted-offender databases, courts have suggested that offenders lose privacy rights by virtue of their offenses. I am skeptical of this “forfeiture of rights” argument as the ground for upholding convicted-offender databases, but it is a common intuition, and many courts have relied on it to overcome the Fourth Amendment claims of convicted offenders. Notice, however, that the right be free from bodily invasion asserted in those cases has no application to near-miss searching. Under current Fourth Amendment doctrine, no "search" occurs in looking at validly obtained DNA profiles to determine if there are any near matches. That said, the disparate-impact concern remains, at least as a policy matter. The inequity exists with or without near-miss searching, but more people are affected if near-miss searching is performed.

The editorial tosses in a practical argument: "the broader the parameters for partial match searches, the more likely false positives become." But what is a "false positive" here? It is not a false conviction. If a close relative did not deposit the crime-scene DNA, then it is improbable that DNA testing of this individual will establish a total match. Testing a falsely identified relative thus will exculpate him. This is not to denigrate the individual's interest in not becoming a "person of interest" to the authorities, even if the interest is temporary, but such false leads are also a concern for the police because they waste time and resources. If the parameters are set so wide as to include large numbers of false leads, then the police will find the technique frustrating, and it will not be used very often. Furthermore, even if the "parameters" were grossly overinclusive, producing many bad near-matches, most of the false leads could be detected in the laboratory with the existing samples from the crime and the nearly matching convicted offenders. If a brother, son, or father of an actual rapist is in the offender database, then he will have the same Y chromosome as the rapist. If the samples do not match at loci on the Y chromosome, then the near-miss offender can be crossed off the list.  In this way, false leads to close relatives of an individual in the database can be largely eliminated by testing at Y-STRs or Y-SNPs in rape cases (or others with male offenders).

Professor Mnookin concludes that "as a matter of fairness, it ought to be all or nothing." Does this mean that (1) either everybody should be in the law-enforcement identification databases or nobody should be, or rather that (2) either everybody should be in the law-enforcement identification databases or only convicted offenders should be? Whichever is intended, she is right about one thing -- near-miss searching is a step in the direction of a more universal database.


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I agree with everything you've written. However, I think the 'racial disparity' argument can be put in a broader (or perhaps separate) way: that familial/near-miss DNA searching augments any existing bad policy in the content of DNA databases. For example, in England, South Australia and the Northern Territory, not only can suspect DNA profiles be placed on a matching database, but they stay there forever, regardless of what happens to the original suspicion. Moreover, in England, volunteers who consent to going on the database can never revoke that consent. Near-miss DNA screening means that these permanent effects are also imposed on those people's near relatives.

This isn't just a problem of abstract principle, but also of policy, for example because near-miss DNA screening increases the police's incentive to use sharp practices in getting suspects' and volunteers' DNA onto the database. That being said, this wrinkle is a (new) reason to object to bad ways that databases are populated, rather than a reason to object to near-miss screening itself.

Posted by: Jeremy Gans | Apr 10, 2007 4:05:28 PM

I haven't read Jennifer Mnooken's column, but I expect I would be largely in agreement with her all or nothing approach. Society, reflecting the views of many ethicists, has, for the most part, decided that one must "earn" one's way into a DNA data base At first, one earned one's way by commiting a serious felony, usually a sex crime. Then in some states it became any felony. Also people arested of or suspected of crimes often had their DNA sampled, and sometimes and sometimes court orders were needed to have one's DNA sample destroyed if chanrges were not filed or there was an acquittal.

I haven't looked closely at what is happening in recent years, and so don't now know where things stand. The important point is that, for good or bad reasons, official society decided that only criminals should have their DNA placed in data bases, making them particularly vulnerable to rearrest should they commit another DNA-leaving crime. (The likely availability of DNA crime scene evidence, together with the costs of typing, was why many states originally limited their data bases to sex offenders. Today's technologies mean, however, that useable DNA can be found at many crime scenes.)

The people who decided what ethics and the law required were, of course, not criminals, nor were they people who expected to find themselves or their relatives suspected of serious crime. Thus they were legislating for others and were willing to allow others (convicted felons) to be especially vulnerable to arrest. But the system they supported meant that if they or people like them committed a rape, for example, all offenses before a first arrest would not be solvable by reference to the data base. This never made sense to me, for I want criminals to be arrested whether it is their first offense or their fourth, and I want first offenders to be deterred by a higher probability they will be caught as much as I want repeat offenders to be deterred.

The privacy rationale was essential to the dominent position. We all have a right to privacy, the argument went, and thus our DNA cannot be incldued in a data base unless we have forfeited that right. How do we forfeit it - by committing some crime. But this is not how it works. Even putting issues relating to uncharged arrestees' DNA and the DNA of those acquitted aside, people with close relatives in a DNA database are themselves at heightened risk to be identified through a DNA search. So some people with unblemished records have a heightened risk of being identified through DNA for a first offense if near misses are allowed to trigger further searches of near relatives.

This might not be too problematic if those in the data base were a random sample of our nation's population. In this case every person with an unblemished record would have a more or less equal chance of being vulnerable to arrest through the follow-up on an imperfect but close DNA match. But as we all know, and as David Kaye pointed out, felons whose DNA is in a data base are disproporitonately members of minorities and of lower social classes. So their never convicted relatives have a much higher probability of being caught should they commit a crime than most whites or members of the middle and upper classes. Thus the class and race biases of the justice system are exacerbated by the creation of convicted felon databases. This, for me, raises serious ethical and equal protection issues.

One solution is to require that reports of trawls through DNA data bases be returned only in the form of reported matches with no indication of near matches. But I don't find such self-restraint likely, and the costs could be great. Suppose, for example, we have a seriel rapist or killer on the loose. How many women will have to be raped or peple killed before we will allow a peak at the DNA serach results to see if, just maybe, a close relative of someone in the data base is very likely the perpetrator? And if, after 10 rapes or murders, we were to pierce this veil and find that we could have stopped the criminal after the first crime, will society ever again tolerate a prohibition on reporting near misses? I think these questions are rhetorical. Thus I believe the only ethical decisions are either to place everyone's DNA signature in a data base, making everyone equally vulnerable to arrest for crimes they commit, or to decide that the privacy costs are so great that we shouldn't have DNA data bases at all. So I expect without having read her argument beyond what David Kaye said, that I agree with Professor Mnookin's all or nothing solution - perhaps.

I have felt this way since I began to think about this issue when I served on the first NRC panel on DNA evidence more than a decade ago. But something has happened since I first considered this issue. The ability to recover DNA from many objects and to type it at the loci used for DNA identifications has dramatically increased. Data base trawls can be used for many purposes today other than to catch those who committed crimes. With everyone's DNA in a database, unscrupulous officials might, for example, be able to identify those who attended a meeting to organize protests against an unpopular war, like the war in Iraq or, if access protections were subverted, those who were trying to organize a union. Moreover, we may not want the degree of enforcement that DNA analysis allows. Do we really want the police to be able to identify, arrest and convict everyone who has smoked a marihuanna cigarette down to the butt and then discarded it?

So the principled decision (whether one agrees with it or not) to limit DNA data bases to convicted criminals, and its irresitable but unprincipled extension to people who happen to be closely related to those in the data base, may still be pragmatically better than the principled decision to place everyone's DNA in a data base, for it diminshes the chance that authorities acting lawlessly can suppress dissent or other protected activities. This is not necessarily what I advocate - despite my concerns I might still opt for a universal data base limited to non-coding alleles - but it does lay out what I see as relevant considerations and the only rationale that I can see for being unprincipled. It should not be of any comfort, but it would not be the first time when our criminal justice system made minorities and the poor more vulnerable to arrest and punishment than it makes "respectable" people, like those reading this blog, who have committed the same crimes.

And finally a glance to the future. The argument for near misses is that this is information that can prevent crime, the person whose DNA came close to the crime scene DNA was properly in the data base because we believe he was especially likely to commit another crime, and we should not reject our good fortune that even though he is innocent his brother is a prime suspect, a crime can be solved and future offending prevented. So, what will happen when people in these data bases die? Then their DNA can no longer identify them, but it can still serve to identify near relatives. Will the DNA of deceased individuals be removed from data bases because there is now no justification for our ability to identify the DNA donor as a criminal - he will not offend again. Or will we keep the DNA in the data base just in case a criminal's DNA closely matches? In other words are the race and class biases that identifying near misses allows simply a side effect of a legitimate search among felons, or are we content to keep the DNA searchable when there is no possibility fo a direct hit. If the latter, it will tell us yet more about ourselves and our justice system.

Rick Lempert

Posted by: Richard Lempert | Apr 26, 2007 8:28:00 PM

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