Wednesday, March 27, 2013

Are Two Heads Better than One? Mathematics and the Amanda Knox Case

In yesterday’s New York Times, “Leila Schneps, a mathematician and mystery writer, and her daughter Coralie Colmez” wrote an op-ed entitled “Justice Flunks Math.” They gave this failing grade to an Italian judge who declined to order a second DNA test in the notorious murder case against the American student, Amanda Knox and her Italian boyfriend, Raffaele Sollecito.

If only the judge understood probability theory, they suggest, he might have ruled in favor of the prosecution's request for another DNA test. In their words:
Whatever concerns the judge might have had regarding the reliability of DNA tests, he demonstrated a clear mathematical fallacy: assuming that repeating the test could tell us nothing about the reliability of the original results. In fact, doing a test twice and obtaining the same result would tell us something about the likely accuracy of the first result. Getting the same result after a third test would give yet more credence to the original finding.
This claim of a mathematical fallacy in the judge’s reasoning, however, rests on an important assumption — that the test results are statistically independent (at least in substantial part). To illustrate their point, Schneps and Colmez explain:
Imagine, for example, that you toss a coin and it lands on heads 8 or 9 times out of 10. You might suspect that the coin is biased. Now, suppose you then toss it another 10 times and again get 8 or 9 heads. Wouldn’t that add a lot to your conviction that something’s wrong with the coin? It should.
But consider this example instead:
You test the surface of a gold coin and test it to make sure it is gold. The test is 90% certain to indicate gold when the metal is gold, so following the advice of Schneps and Colmez, you repeat the test three times and strike gold each time. When you try to sell the coin, however, a more astute buyer weighs it and finds that it does not have the density of gold. It is, in fact a thickly gold plated, lead coin.
Which example is more apt in the Knox case? A Nature blog explained that "[v]ery small amounts of Knox’s DNA were found on a knife located at the crime scene 46 days after Kercher’s murder," but this is not correct. The knife came from Sollecito's kitchen, and a more informed account in the New York Times states that "the court-appointed experts concluded that ... Ms. Knox's DNA was in fact on the handle" -- hardly a surprise given that she may have used it to cook dinner in her boyfriend's apartment. The only thing that made the knife incriminating was a police laboratory finding of DNA from the victim, Meredith Kercher, on the blade. But there was evidence that the knife could not have produced all the wounds, and the court-appointed experts were skeptical of the finding about the blade as well the police laboratory's analysis of "a bra clasp that belonged to the victim found on the floor at the scene 46 days after her murder" said to show Sollecito’s DNA.

Returning to Nature's account:
Speaking at the request of the defence, two forensic scientists, Stefano Conti and Carla Vecchiotti from Sapienza University in Rome, said police investigators failed to follow international protocols for collecting and handling evidence and conducting tests on small genetic samples known as low-copy-number (LCN) DNA analysis. For example, officers were not wearing protective masks or hair caps at the crime scene. ... In addition, Conti said police often used plastic bags, rather than paper, to wrap evidence, heightening the risk of contamination. ... “There are various circumstances do not adhere to protocols and procedures,” Conti told the court.

Consequently, the independent experts concluded that they could not rule out the possibility that the knife and bra had been contaminated by other sources of Knox’s and Sollecito’s DNA, such as other evidence at the crime lab where forensic testing was taking place.
If these experts’ concern — that the original DNA test was simply detecting traces of Kercher's and Sollecito’s DNA that investigators inadvertently transferred to the knife and bra clasp, respectively — then repeating the tests could well continue to detect that DNA — and prove nothing more than the original tests did. If the bra clasp sample showed a mixture of DNA from the victim and Sollecito (and nothing else), for example, then repeating it over and over would not reinforce the prosecution case in the slightest. It would be no different than retesting the surface of the lead coin with its gold plated contamination. The inability of the DNA evidence to demonstrate a convincing link to the defendants would remain after even an infinity of new tests.

Consequently, it is hard to judge Schneps' and Colmez's suggestion that "[t]he judge’s rejection of the retest — at least based on the notion that a confirming retest could tell us nothing about the likelihood that the DNA was a match — was a serious error, one that scuppered an opportunity to get at the truth of Ms. Kercher’s murder."

The judge’s decision may have been mathematically sound, or it may have been as naive and fallacious as Schneps and Colmez propose. They have a nice theory but it is fair to assume that there were uncontaminated samples for new testing? Without some specification of precisely what made the initial testing problematic and whether those problems could be reduced sufficiently with retesting, it seems precipitous to convict the judge who overturned the guilty verdict of "bad math."

Indeed, Schneps and Colmez seem to believe that the judge ignorantly opposed retesting of the small sample of DNA on the blade despite an improvement in the technology of testing low template DNA. They wrote that
Even though the identification of the DNA sample with Ms. Kercher seemed clear, there was too little genetic material to obtain a fully reliable result — at least back in 2007. By the time Ms. Knox’s appeal was decided in 2011, however, techniques had advanced sufficiently to make a retest of the knife possible, and the prosecution asked the judge to have one done. But he refused.
Yet, the judge clearly was open to new methods. He asked the two university experts to ascertain "whether it is possible, by means of a new technical analysis, to identify the DNA present on items 165b (bra clasp) and 36 (knife)." The Conti-Vecchiotti Report, Assignment. Finding "no evidence of cellular material in the samples analyzed," however, his experts concluded that "no DNA suitable for further laboratory investigations (amplification, electrophoresis) was present either on the swabs [tamponature] (A-B-C-D-E-F-G-H-I) taken from Exhibit 36 (knife) or on those (L-M) taken from Exhibit 165B (hooks of the bra)." Id. Conclusions (1). They based this conclusion on the absence of cellular material and the failure of "quantification of the extracts ... conducted via Real Time PCR [to] reveal the presence of DNA." Id. Conclusions (2).

The prosecution disagreed. It asked for still more testing. But Judge Claudio Pratillo Hellmann had had enough. Rather than prolong the appeal -- and the imprisonment of the defendants -- still longer to await tests that his experts told him would be useless, he and the jurors returned their not-guilty verdict. It remains to be seen why this verdict now has been overturned, but it is hardly obvious that "bad judicial math" is the reason.

Later Postings

Monday, March 25, 2013

In Press: Confronting Science: Expert Evidence and the Confrontation Clause

The coming volume of the University of Chicago's Supreme Court Review will include an assessment of the Supreme Court's trilogy of opinions on the Confrontation Clause and laboratory reports: Jennifer L. Mnookin and David H. Kaye, Confronting Science: Expert Evidence and the Confrontation Clause, preprint available at
Abstract: In Crawford v Washington, the Supreme Court substantially changed its understanding of how the Confrontation Clause applies to hearsay evidence. Since then, the Court has issued three bitterly contested expert-evidence-related Confrontation Clause decisions, and each one has generated at least as many questions as answers. This article analyzes this trilogy of cases, especially the most recent, Williams v Illinois.

In Williams, the Court issued a bewildering array of opinions in which majority support for admitting the opinion of a DNA analyst about tests that she did not perform was awkwardly knitted together out of several incompatible doctrinal bases. The most prominent and fully developed argument for admission was that the references to the work of the analysts who actually did the testing but who never testified were admitted for a purpose other than their truth. Although we maintain that this argument is, on the facts of Williams, implausible, we also recognize that in other, relatively limited instances, expert basis evidence might legitimately be introduced for a purpose other than its truth.

After striving for precision on this doctrinal point, we step back and suggest that the ongoing anxiety about how to think about expert evidence and the Confrontation Clause exists in large part because the Court has yet to face directly a set of larger, background concerns. There is significant uncertainty about how, and to what extent, scientific evidence should be treated as special or distinct from other kinds of evidence for confrontation purposes. We suggest that scientific and expert evidence might warrant some limited special treatment, based on what we see as one of the most critical dimensions of scientific knowledge production—that it is a collective, rather than an individual enterprise. Recognizing that scientists inevitably rely and build on facts, data, opinions, and test results of others, we suggest that courts should engage in a modest form of scientific exceptionalism within Confrontation Clause jurisprudence, through efforts to create procedures that respect the fundamental values of the Confrontation Clause, but also adapt when necessary, to the epistemic structures and processes of science.

In Press: The Database and the Dictionary

An improved (I hope!) version of an earlier post on the Ohio Supreme Court's opinion in State v. Emerson will be published in Jurimetrics: The Journal of Law, Science, and Technology (53:4). The current draft is available at
Abstract: In State v. Emerson, 981 N.E.2d 787 (Ohio 2012), the Ohio Supreme Court discerned neither a statutory nor a constitutional barrier to retaining an acquitted defendant’s DNA profile in the state’s database when the profile was obtained with a search warrant and the defendant did not request expungement of the database record. The court wrote that the profile fell with the statutory category of “records from forensic casework or from crime scenes” and that “a person does not have standing to object to the retention of his or her DNA profile or to the profile's use in a subsequent criminal investigation.” This essay disputes both these conclusions. It argues that placing or retaining the profile of an acquitted individual, even one obtained with a warrant, in a database for convicted offenders violates the statute and that the affected individual has standing to complain. It concludes, however, that the entry and use of the profile in the database, although not statutorily authorized, does not contravene the Fourth Amendment.

Sunday, March 24, 2013

Disgusting DNA

The Whooper Stopper

When my son worked at a pizza restaurant a long time ago, he told me that some of the kids preparing the food would spit into into their handiwork. I tried not to think about it, but the practice, at a Burger King in Vancouver, Washington, has prompted a major decision on the tort of intentional infliction of emotional distress.

The employee with the loose lips probably did not expect the Whopper with cheese to go directly to the police, but Clark County Deputy Sheriff Edward Bylsma evidently had a well honed sense for the suspicious. After receiving his burger from a drivethrough window, he stopped in a parking lot, removed the top bun, and uncovered a “slimy, clear and white phlegm glob” on the meat.

According to the Huffington Post, "Deputy Bylsma felt ill all day; he claims that he even vomited on account of his emotional distress. He sent the burger away for DNA testing to try and trace the spit back to an individual person. When the results linked the loogie to Burger King employee Gary Herb, Bylsma moved to sue Burger King. He said that he became unable to eat food from restaurants and lived in fear of contracting a foodborne illness."(How the deputy acquired a reference sample from Mr. Herb is not apparent from news accounts.)

A federal judge dismissed the 2009 case against Burger King for negligence, product liability and vicarious liability because the Washington Product Liability Act [WPLA] does not provide for damages for emotional distress in the absence of physical injury. Or so it thought. The Ninth Circuit asked the Washington Supreme Court to rule on the scope of its tort law, and last month, the state court wrote that "[t]he courts of this state recognize damages for ... emotional distress, and thus, such damages, if proved, are recoverable under the WPLA." It added that "[t]he WPLA permits relief for emotional distress damages, in the absence of physical injury, caused to the direct purchaser by being served and touching, but not consuming, a contaminated food product, if the emotional distress is a reasonable response and manifest by objective symptomatology."
Of course, whether the deputy will recover at trial (if it comes to that) remains to be seen. Will Burger King argue that the deputy, whose job may require him to view grisly scenes of human violence and carnage, is overstating his symptoms?

Moving Violations

In England, the national DNA database has been employed to curb spitting on transit workers. As part of Operation Gobstopper, bus drivers in northwest London received 2,500 evidence collection kits. Tube staff in central London and train wardens in Scotland were similarly equipped, the BBC reported in 2004.

The kits helped prosecute about 100 people on the Tube in 2007. Reportedly, 7 out of 10 samples yielded a match to DNA profiles in the national database of criminal offenders and arrestees.

Update of Mar. 25, 2013: The Whopper case, Bylsma v. Burger King Corp., 293 P.3d 1168 (Wash. 2013), did not involve a database search. Only two employees, an Herb and a McDonald, had been working in the restaurant.When police visited the restaurant that night and asked for saliva samples, the two refused. The state crime laboratory determined that the saliva on the burger was of human origin. The police returned with search warrants, and the laboratory named Herb as the source of the spit. Herb pleaded guilty to felony assault (although the spit was not initially visible and only touched Bylsma because he placed his finger in it to test its consistency) and was sentenced to 90 days in jail. (Thanks to Jeremy Gans, whose comment provided a link to the civil complaint setting forth these facts).

Saturday, March 23, 2013

Hot Off the Presses: Beyond Uniqueness

The Birthday Problem, a classic puzzler of probability theory, has a counter-intuitive answer. Statisticians on the National Academy of Sciences' Committee on Forensic DNA Evidence: An Update, used the problem to distinguish two arguments that might support the conclusion that DNA types are unique in a population. Years later, law and business school professor Jay Koehler used the same problem to show how difficult it is to demonstrate total uniqueness -- and what other kind is there? -- of toolmarks on the basis of the collective experience of toolmark examiners. A report of a NIST (National Institute of Standards and Technology) expert working group on latent fingerprint analysis also invoked the problem to explain why even a tiny random match probability does not establish that fingerprint images are discernibly unique. Nevertheless the Birthday Problem cannot refute a claim that examiners making source attributions from almost unique features will almost never be wrong. (Of course, this observation does not mean that a claim of almost no errors in case work would be true.)

The relationship between a small number of duplicates and individualization in the sense of source attribution was the subject of a paper presented at the Eighth International Conference on Forensic Statistics in 2011. An updated version of the paper appeared this month as Beyond Uniqueness: The Birthday Paradox, Source Attribution, and Individualization in Forensic Science Testimony, Law, Probability and Risk, Vol. 12, March 2013, pp. 3-11. Regrettably, the publisher, Oxford University Press, forbids authors from posting the final versions of articles in the journal, but an earlier draft is available on SSRN.
Abstract: For many decades, forensic science identification experts have insisted that they can ‘individualize’ traces such as fingerprints and toolmarks to the one and only one object that produced them. They have relied on a theory of global uniqueness of patterns as the basis for such individualization. Although forensic practitioners and theorists are moving toward a more probabilistic understanding of pattern matching, textbooks and reference works continue to assert that uniqueness justifies individualization and that experience demonstrates discernible uniqueness. One response to the last claim applies a famous problem in probability theory — the Birthday Problem — to the forensic realm to show that even an extensive record of uniqueness does little to prove that all such patterns are unique. This essay describes the probabilistic reasoning and its limits. It argues that the logic of the Birthday Paradox does indeed undercut the theory of global, general uniqueness, but that the reasoning is logically compatible with opinion testimony that a specific object is nearly certain to be the source of a pattern or trace. It also notes some alternatives to categorical claims of individualization, whether those claims are based on the theory of global, general uniqueness or instead on some less sweeping and more defensible theory.

Hot Off the Presses: Chimeric Criminals

Nearly two years ago, I raised a question about the depth of the documentation and analysis in the book Genetic Justice by Sheldon Krimsky and Tania Simoncelli. A discussion of chimerism and the threat it supposedly poses to DNA exonerations prompted the following debunking essay: Chimeric Criminals, Minnesota Journal of Law, Science, and Technology, Vol. 14, No. 1, Winter 2013, pp. 1-9. It is available from SSRN or on the review's website.
Abstract: According to some commentators, an obscure genetic condition known as chimerism “could undermine the very basis of the forensic DNA system” and force a reconsideration of “the entire project of forensic DNA.” This conclusion is as unfounded as it is unnerving. Chimerism is a consideration in, but not a real obstacle to DNA identification. This essay explains why.

Hot Off the Presses: On the 'Considered Analysis' of Collecting DNA Before Conviction

The final version of On the 'Considered Analysis' of Collecting DNA Before Conviction, mentioned three months ago, is now published in UCLA Law Review Discourse, Vol. 60, 2013, pp. 104-126, and is available on the review's website or from SSRN.
Abstract: For nearly a decade, DNA-on-arrest laws eluded scrutiny in the courts. For another five years, they withstood a gathering storm of constitutional challenges. In Maryland v. King, however, Maryland's highest court reasoned that usually fingerprints provide everything police need to establish the true identity of an individual before trial and that the state's interest in finding the perpetrators of crimes by trawling databases of DNA profiles is too "generalized" to support "a warrantless, suspicionless search." The U.S. Supreme Court reacted forcefully. Chief Justice Roberts stayed the Maryland judgment, writing that "given the considered analysis of courts on the other side of the split, there is a fair prospect that this Court will reverse the decision below." The full Court then granted a writ of certiorari. This essay briefly examines the opinions listed by the Chief Justice and finds their analysis incomplete. I outline the Fourth Amendment questions that a fully considered analysis must answer, identify questionable dicta on the definition of "searches" and "seizures" in the opinions, describe a fundamental disagreement over the analytical framework for evaluating the reasonable warrantless searches or seizures, and criticize a creative compromise in one of the opinions that would allow sample collection without DNA testing before conviction. I conclude that in King, the Supreme Court not only must assess the actual interests implicated by pre-conviction collection and profiling of DNA but also should articulate the appropriate framework for evaluating the reasonableness of warrantless searches in general.

Monday, March 11, 2013

The Oral Argument in Maryland v. King -- Part V

It is time to sum up and read the tea leaves that are in the transcript of the February 26th oral argument in Maryland v. King. Previous postings concerned these topics:

Part I
  • Whether taking DNA profiles of arrestees is distinguishable from acquiring them from the general population;
Part II

  • Whether deriving information from database trawls that could inform pretrial release decisions and conditions can constitute a special need for warrantless DNA acquisition now or in the future;
 Part III
  • Whether DNA profiles are distinguishable from fingerprints on the theory that collecting fingerprints is not even a search;
  • Whether DNA samples are distinguishable from fingerprints because DNA samples contain more personal information;

Part IV
  • Whether Kyllo's analysis of thermal imaging of a home applies to DNA profiling;
  • Whether the Court's precedents show it is unwilling to trust the government;
  • How Skinner, Greenwood, and Davis (4th Cir. 2012) affect the claim that a laboratory analysis limited to identifying features is a search in its own right.
At least some of the Justices appeared to be searching for a theory that would distinguish routine DNA collection and analysis before conviction (DNA-BC) for arrestees from the DNA-BC for everyone in the population. But why?

Sure, it sounds more moderate to approve existing laws (if that is what these Justices decide to do) on a theory that shows that the databases never could be expanded to the entire population (without a constitutional amendment). Nevertheless, that is not likely to happen anyway, and stepping back from the rococo structure of Fourth Amendment doctrine and probing the pertinent interests, it seems that the legitimate privacy interests in avoiding a record of purely identifying features are weak. Blood samples already are taken for screening newborn children for certain genetic diseases (a special need), and it would not hard to add loci that be would suitable for identification and to upload these data while keeping the samples entirely within the health care system.

Of course, most children will never grow up to commit crimes for which DNA traces will be found, so the government's interests in having a population-wide identification database also are limited. But severing routine DNA collection from contacts with the criminal justice system has an egalitarian appeal. It would avoid the class- and race-based imbalance in the databases populated by profiles from individuals who have been arrested or convicted.

Will the Court uphold DNA-BC for arrestees on one theory or another? I suspect so, but given the Justices' statements during the argument and their positions in previous Fourth Amendment cases, it could be a close case with three or more separate opinions. Justice Alito seemed especially impressed with the law enforcement value of DNA databases. The Chief Justice's opinion staying enforcement of the Maryland law also treated this as a major consideration. Justice Breyer emphasized the limited threat to personal privacy. Justice Kennedy seemed content with the incantation "incident to arrest," and he has strongly supported the power of the state to compel a person to produce identification. See Orin Kerr, Balancing Versus the Warrant Requirement: A Few Thoughts on Maryland v. King, SCOTUSblog, Feb. 18, 2013 (discussing Justice Kennedy’s opinion in Hiibel v. Sixth Judicial District Court). That could be four votes to uphold the practice right there.

Justices Kagan and Sotomayor seemed to be leaning the other way, using the analogy of a search of a house and noting the absence of an existing exception to the warrant-and-probable-cause requirement. Justice Scalia appeared to reason that the case is a classic trespass on the person that historically would have been unacceptable without probable cause. Will that be as far as his analysis goes? Justice Ginsburg noted that DNA-BC, although "very reliable" was not based on individualized suspicion. These could be four votes to end DNA-BC.

Justice Thomas was characteristically silent at the argument. He wrote the balancing opinion in Samson on which Maryland relies and generally tends to reject challenges to search under the Fourth Amendment. If he sees DNA databases as a development not governed by the original understanding of the framers, he may well find the balancing arguments of the state and federal governments sufficient.

In the end, my money is on a 5-4 (or maybe 6-3) decision for the state. But I am not prepared to wager more than a nominal amount. As opinions are drafted and exchanged, the Justices easily could modify the positions they hinted at in the oral argument. Lots of issues are swirling about in this case. The opinions that emerge by the end of June could be important not only for the many states that have adopted or are considering adopting DNA-BC, but also for the zigzagging development of Fourth Amendment doctrine.

Wednesday, March 6, 2013

The Oral Argument in Maryland v. King — Part IV

The previous installment of this series described counsel’s answers to questions as to how DNA profiling is different from fingerprinting. After pointing out that “there are profound privacy concerns associated with the government's collection of an individual's DNA” because “when you evaluate the entirety of an individual's DNA, there is a great deal of personal information contained there,” counsel for Mr. King added that
Now, the government's response to that is essentially the "just trust us" defense; namely that the government is not looking at all that information, it is only looking at a certain subset of that information. But that has never been how this Court has analyzed privacy interests, at least outside the special needs context. Probably the closest analog is this Court's decision in Kyllo v. United States, where the Court said that it was of no moment that the heat-sensing device that was at issue in that case did not detect any information about the intimate details of activities within the home.
I think this is inaccurate (or at least incomplete, as oral argument often is). First, the Supreme Court has been willing to trust the government with highly private information. Whalen v. Roe, 423 U.S. 1313 (1975), provides an illustration. In Whalen, physicians prescribing, and patients receiving, prescriptions for certain addictive drugs argued that the patients’ right of privacy prevented New York from establishing a database of these drug prescriptions by compelling physicians to send to the state information on “the prescribing physician; the dispensing pharmacy; the drug and dosage; and the name, address, and age of the patient.” That an individual is being treated with powerful medications is profoundly informative, but New York insisted that it could be trusted to use the private information as mandated in the statute. The Court agreed, stating that even though “employees may violate the statute by failing, either deliberately or negligently, to maintain proper security of the computerized data bank, ... [t]here is no support in the record ... for an assumption that the security provisions of the statute will be administered improperly.”

Furthermore, a search warrant must describe with particularity the areas to be searched and the items sought. We trust the state to execute the search in accordance with these limits (although it can take advantage of its observations of other evidentiary items or contraband in plain view). Analogously, in King, the Court can authorize DNA profiling strictly for regions of the genome that are useful for identification but not for drawing inferences about medical conditions or other matters that would not otherwise be apparent in an arrestee.

Second, Kyllo is not particularly analogous to collecting biometric data from an arrestee. The Kyllo Court determined only one thing — thermal-imaging of a home amounted to a search of the premises — even if it was only analogous to a very minor entry into the home (say, opening the door to look at a square inch of the floor). Writing for the Court, Justice Scalia maintained that “[i]n the home, our cases show, all details are intimate details, because the entire area is held safe from prying government eyes.” Moreover, he added, even “the relatively crude equipment at issue here ... might disclose, for example, at what hour each night the lady of the house takes her daily sauna and bath ... .”

Kyllo does not prevent the Court from considering the extent to which a practice that is not comparable to an invasion of the home affects legitimate privacy interests. One needs some further argument to conclude that the nature of the information being acquired is irrelevant. The security-privacy interest in the home is one thing. The pure informational-privacy interest in biometric data is another. The two cannot be automatically equated.

Although the inconclusive Kyllo analogy might play some role in the opinions that ultimately emerge in King, it did not engage any Justices at the oral argument. However, the Chief Justice did evince some doubt about the assertions about deeply private information, for he referred to the ease with which anyone can obtain genetic information:
CHIEF JUSTICE ROBERTS: You disclose all of this intimate private information when you take a drink of water and leave — leave the glass behind.

MR. SHANMUGAM: But, Mr. Chief Justice, as I said at the outset, we believe that there might still be — indeed, we think the better view under this Court's cases is that there would still be a Fourth Amendment search there. The only difference would be that you don't have the intrusion into the body that makes the question of whether or not there is a search here an easy one. ...
The Chief Justice’s question points to the shallowness of the public exposure theory that counsel for Mr. King had used to distinguish DNA molecules from fingerprint images. As I noted yesterday, he seemed to say that fingerprinting was not a search just because the fingers that produce the print are visible in public. If that is enough to defeat a reasonable expectation of privacy for fingerprints, why does not the visibility of bodily fluids that contain the DNA sequences defeat the same expectation for those features?

The better argument is that, whether or not fingerprinting should be considered a search, the informational privacy interest in the entirety of the genome demands treating the acquisition of that information as a search that must be justified under the Fourth Amendment. I am sympathetic to this argument (and have made it myself in Kaye (2001)), but the Court’s opinions on the Fourth Amendment as a guarantee of purely informational privacy are less clear than one might think. It is true that some opinions speak of urinalysis as if it is a Fourth Amendment search in and of itself. But the case usually cited for this proposition, Skinner v. Railway Labor Executives Ass'n, 489 U.S. 602 (1989), involved both an informational privacy concern and disquiet over the manner in which the sample is obtained. In addition to observing that urinalysis could “reveal a host of private medical facts … , including whether [someone] is epileptic, pregnant, or diabetic” the Skinner Court considered the “process of collecting the sample to be tested, which may in some cases involve visual or aural monitoring of the act of urination, [that] itself implicates privacy interests.” Id. at 617.

The Skinner Court may or may not have considered the privacy interest in the act of urination to be critical, but it remains a part of the holding in the case. Skinner therefore does not conclusively resolve the question of what the outcome should be if the procedure the state uses to collect the bodily fluids does not itself offend the Fourth Amendment.

One answer is that it depends on the nature and extent of the information that the laboratory tests reveal. The point here, however, is that Mr. King’s answer that “there would still be a Fourth Amendment search there” is not all that apparent “under this Court’s cases.” (I examine some of these cases further in the articles listed at the end of this posting.)

Justice Alito did not seem inclined to accept the broad view that every form of DNA analysis, divorced from the process of collecting the DNA molecules, is a search “under this Court’s cases.” He asked:
JUSTICE ALITO: What if someone has a bloody shirt and throws it away in the trash — in a public trash can along the street, you are saying that the police can't analyze that without a search warrant?
The unmistakable reference here is to California v. Greenwood, 486 U.S. 35 (1988). There, a police officer acquired opaque, plastic bags left on the curb outside a house and picked up by a private trash collector. She opened the bags and located “items indicative of narcotics use.” The Supreme Court (in an opinion that I and many commentators on the case find less than fully convincing), reasoned
that respondents exposed their garbage to the public sufficiently to defeat their claim to Fourth Amendment protection. It is common knowledge that plastic garbage bags left on or at the side of a public street are readily accessible to animals, children, scavengers, snoops, and other members of the public. ... Moreover, respondents placed their refuse at the curb for the express purpose of conveying it to a third party, the trash collector, who might himself have sorted through respondents' trash or permitted others, such as the police, to do so. Accordingly, having deposited their garbage “in an area particularly suited for public inspection and, in a manner of speaking, public consumption, for the express purpose of having strangers take it,” ... respondents could have had no reasonable expectation of privacy in the inculpatory items that they discarded.
Id. at 40-41. Suppose, then, that the trash also contained Justice Alito’s bloody shirt. It is hard to imagine that the Greenwood Court would have said that a person who has no reasonable expectation that the police will not paw through his garbage for narcotics paraphernalia reasonably could expect that they would not analyze the blood on the shirt.

Without mentioning Greenwood, counsel pointed to a Fourth Circuit opinion:
MR. SHANMUGAM: The argument would be that the subsequent analysis of the DNA nevertheless still constitutes a search. And the most significant decision on this issue to date is the Fourth Circuit's decision in United States v. Davis, which I would encourage you to look at if you are interested in this issue, because it holds that the extraction of the DNA from an item that was lawfully in the government's custody still constitutes a search.
United States v. Davis, 690 F.3d 226 (4th Cir. 2012), is indeed “significant.” It is significantly different from every opinion on “abandoned” or “shed” DNA. Every appellate court to consider traces of saliva on envelopes, cups, bottles, and the like has held that the laboratory analysis is not a search because the individual who left the cells has no reasonable expectation of privacy in the DNA molecules.

Davis does not mention these cases (it is not itself an “abandoned” DNA case),* and the Supreme Court has long endorsed other court of appeals’ opinions treating laboratory analyses of legitimately acquired material as something less than Fourth Amendment searches. See United States v. Edwards, 415 U.S. 800 (1974). Despite these obstacles, the Court of Appeals took the position that even though the police acquired the DNA without violating the Fourth Amendment, and even though the laboratory analysis was confined to the normal, identifying loci, the laboratory work violated a reasonable expectation of privacy and, hence, was a search.

The Supreme Court in King is unlikely to adopt the Fourth Circuit’s position, for it can recognize that swabbing the inside the mouth for cells is a search even if it the government can be trusted to confine its use of the DNA to deriving strictly identifying features. In assessing the constitutionality of the entire DNA database system, it can consider how destructive that procedure is of personal integrity and informational privacy without embracing the conclusion that the mere act of “reading” the DNA is, in and of itself, a search.


* The facts in Davis are rather unusual. Earl Davis showed up at a hospital saying that a robber had shot him in the leg. A police officer took went to interview him there. The officer took Davis’s street clothes, which were in a plastic bag under the hospital bed. The Fourth Circuit determined that the warrantless seizure was permissible because the clothes were in plain view and plainly were relevant to an investigation of the alleged robbery. The investigation led nowhere, but police later used the clothes to obtain Davis’s DNA profile in a murder investigation. His DNA exonerated him, but the police placed the DNA profiles in a local DNA database. It matched DNA found in a still-later murder-robbery case, and that was the match that led to Davis’s prosecution and conviction.

  • David H. Kaye, On the “Considered Analysis” of DNA Collection Before Conviction, UCLA Law Review Discourse, Vol. 60, March 2013, available at
  • David H. Kaye, A Fourth Amendment Theory for Arrestee DNA and Other Biometric Databases, 15 U. Pa. J. Const. L. No. 4 (forthcoming 2013), available at
  • David H. Kaye, The Constitutionality of DNA Sampling on Arrest, 10 Cornell J. L. & Pub. Pol'y 455 (2001), available at 
Related Blog Postings

Monday, March 4, 2013

The Oral Argument in Maryland v. King — Part III

At the oral argument in Maryland v. King, the Justices wanted to know why DNA collection and databases were more personally intrusive or destructive to other privacy interests than fingerprint collection and databases. In response, Mr. King’s counsel advanced two formal, doctrinal points: He questioned whether fingerprinting even amounted to a search (because fingers are external and visible); and, referring to the limits on the "special needs" doctrine (see yesterday's posting), he emphasized that fingerprint systems create a permanent record of individual identity for authentication of identity, whereas, at the moment, DNA is primarily used for the criminal intelligence purposes. He also mentioned the most fundamental point — that DNA samples reveal more about an individual than his fingerprints — but the Justices did not pursue it directly.

Let us look at the exchanges on the nature of fingerprinting in more detail. Justice Alito focused on the methods collecting fingerprint and DNA samples when he asked:
JUSTICE ALITO: Well, do you think the intrusion is worse when you just take a swab and you go inside somebody's cheek, as opposed to rolling fingerprints?* Which is the greater intrusion?
Apparently, Mr. King’s position was that because the swab goes into the mouth, DNA sampling is the more invasive procedure:
MR. SHANMUGAM: Well, we think that it is settled that intrusions into the body constitute a search for Fourth Amendment purposes.

JUSTICE ALITO: Which is [the greater intrusion?]—

MR. SHANMUGAM: I suppose that the argument could be made, Justice Alito, that there is a similar trespass on the person and, therefore, a search when fingerprints are collected. I would note parenthetically that in the first half an hour of this argument we heard no explanation either by the state or by the federal government as to their theory as to why fingerprinting is constitutional. Now, we —
Justice Alito persisted in his demand for a more satisfying explanation of the difference:
JUSTICE ALITO: Well, the thrust of a lot of what we have been presented with in the briefs and what we have heard this morning — and by the way, I think this is perhaps the most important criminal procedure case that this Court has heard in decades — the attorney for the State began by listing a number of crimes just in Maryland that had been solved using this. So this is what is at stake: Lots of murders, lots of rapes that can be — that can be solved using this new technology that involves a very minimal intrusion on personal privacy. But why isn't this the fingerprinting of the 21st century? What is the difference? If it was permissible — and it's been assumed to be so for decades — that it is permissible to fingerprint anybody who's booked, why is it not permissible to take a DNA sample from anybody who is arrested?

MR. SHANMUGAM: Justice Alito, we think that fingerprinting is distinguishable on three grounds. First of all, as a practical matter, an individual's DNA contains far more information and far more personal information than an individual's fingerprints. But as a doctrinal matter, we think that fingerprinting is distinguishable —

JUSTICE ALITO: Well, as to the first, in our cases involving searches for — where a urine sample is taken to determine drug use, the urine can be analyzed for all sorts of things besides the presence of drugs, and the Court has said in those cases, we are only going to consider that — we are considering that this is a reasonable search with respect to the determination of whether the person has taken drugs, not all the other information ... that can be obtained from it.

MR. SHANMUGAM: But that is because, Justice Alito, in those cases, cases like Skinner and Von Raab and Vernonia, there was a special need apart from the ordinary interests in law enforcement. And here it is clear that the primary purpose of the Maryland statute and, indeed, the similar statutes on the federal and state levels was the ordinary interest in crime control, to solve unsolved crimes. And that is why those special needs cases are distinguishable, and I think that's why the state essentially disavows any reliance on the special needs doctrine.
So far, the question of how collecting DNA compares in its intrusiveness to recording fingerprints has gone largely unanswered. Justice Breyer certainly was not satisfied that the degree of intrusion was greater for a cheek swab:
JUSTICE BREYER: [I]f I look in terms of intrusion —  [and] I am not talking legally, I am talking practically — ... I can argue that it is certainly a much lesser intrusion than fingerprints. You [only] have to stand there, have the thing rolled, stick out your tongue. I mean, it's hard to say it's more [intrusive — at least] for me. I'm not saying for others. ...
Justice Breyer’s suggestion that having a swab inserted into one’s mouth is less invasive than having one’s fingers inked and rolled onto a card hardly seems convincing. My intuition is that the swabbing adds to the demeaning and humiliating nature of a modern, custodial arrest more than fingerprinting. Nevertheless, any difference in the level of offensiveness is slight, and the very question seems to miss the real point. If the limited invasion of the body were the decisive factor, then the government could sidestep the concern entirely by scraping some cells from the surface of the skin. A sticky pad might supply enough DNA for profiling, making the procedure indistinguishable from fingerprinting in terms of the physical intrusion.

At this point, then, we are left with one distinction between fingerprinting and DNA sampling — that “[f]irst of all, as a practical matter, an individual's DNA contains far more information and far more personal information than an individual's fingerprints.” Obviously, this concern about informational privacy has nothing to do with the process by which the information is obtained. It would apply even if DNA could be analyzed at a distance, with no physical contact between the police and the suspect.

But the Court did not immediately pursue this proffered distinction. Instead, Justice Kagan asked:
JUSTICE KAGAN: What are your other two distinctions?

MR. SHANMUGAM: With regard to fingerprinting, we think that, notwithstanding the physical intrusion involved with taking an individual's fingers and putting them on the pad, that the better view is that fingerprinting is not a search, and to the extent that this Court has addressed the question it has suggested that fingerprinting is not a search because an individual has no expectation of privacy in their fingerprints because their fingers are constantly exposed —
Now, there are some lower court cases that take this point of view, but it seems to undercut Mr. King’s position. If fingerprints are not a search because the fingers that produce them are constantly exposed to public view, then DNA profiles are not a search because cells that contain DNA also are constantly exposed. To be sure, the Supreme Court has suggested (and held) that the Fourth Amendment does not shield features such as one’s voice and face that are constantly exposed to public view, but the Court has never considered whether recording or comparing fingerprints constitutes a search. The few Supreme Court cases finding fingerprints to have been unconstitutionally obtained have simply treated the detention of the individual—a seizure of the person—as the event that triggered the protection of the Fourth Amendment, and the personal interest in freedom of movement is the same for DNA collection as for fingerprinting.

It was at this point that Justice Breyer made the remarks quoted above, and he went on to express skepticism of the informational privacy claim as well:
JUSTICE BREYER: And by the way, when you talk about what information you could get out of it, there is a brief filed by leading scientists in the field. And I came away from the brief thinking there isn't much more information, because fingerprints can be abused, too. Of course, you can learn loads from fingerprints. Photos, try photos; my God, you could learn a lot: Who he was, who — you know, so all these things could be abused. But I came away from that brief, frankly, to think, well, in terms of the possibility of abuse, it's there, but [it’s also present with] these other things, photos, too. ... Now, you tell me in light of that hostile question (laughter) [how] it's different from fingerprints and worse because of one, two, three, and I will write it down and I'll remember it.

JUSTICE SCALIA: He gave us one and two. I have been waiting for three. Will you drop the shoe? (Laughter.)

MR. SHANMUGAM: Let me — I will gladly get to three with regard to fingerprinting ... . [W]e think fingerprinting is different, above and beyond the fact that we think ... that fingerprinting is not a search, ... because fingerprinting as it is currently practiced does serve a special need. The primary purpose of fingerprinting is to identify an individual who is being taken into the criminal justice system.
If Justice Breyer did write down Mr. King’s proposed distinctions, he might have the following list: (1) DNA samples contain more information than fingerprint records; (2) collecting and using fingerprint records should not be considered a search because fingers are visible; and (3) fingerprints are taken on arrest primarily to ascertain whether an individual is who he claims to be and to see if he has a criminal record (and only secondarily to connect arrestees to crimes through comparison to latent prints). The latter two proposed distinctions are important only with respect to nuances of contestable caselaw. They do not directly address the fundamental question of the relative invasion of personal interests. In this regard, the only direct answer on the list is that “an individual's DNA contains far more information and far more personal information than an individual's fingerprints.”

Still, this is an important answer. I had expected the informational privacy issue to provoke more discussion. Although counsel for Mr. King later stressed the issue in a reply to Justice Sotomayor,** only Justice Breyer picked up on it, and in doing so, he became the first jurist (to my knowledge) to recognize that fingerprint patterns are not entirely devoid of personal information.

Fingerprints have a genetic component, and the scientists’ brief to which Justice Breyer referred has a three-and-one-half page appendix listing “some studies reporting diseases associated with fingerprint features.” This brief (discussed in "Scientists' Brief" on CODIS Loci: Q & A) focused on the information content of CODIS profiles, not samples. It suggested that even these profiles contained somewhat more personal information (being fully inherited characteristics) than fingerprint patterns (being influenced by both genes and the uterine environment).

The brief does not dispute — indeed, it presupposes — that DNA samples are replete with information. Yet, the issue of sample retention did not arise in the argument, and a few of the Justices even suggested that the ease with which police and private parties can acquire samples in other ways might defeat a reasonable expectation of privacy. The next posting will turn to this issue of “shed” or “abandoned” DNA.


* “Rolling” refers to the process by which each inked digit is rotated slightly from side to side while pressed on a cardboard surface to yield a permanent, ten-print card. Digital scanning is growing more common, but Justice Alito may have picked the messier inking process as the procedure to be compared because, for many years, lower court had upheld as constitutional fingerprinting arrestees in that manner, and Justice Alito regarded these holdings as correct.

** JUSTICE SOTOMAYOR: I was interested in [whether] there is something inherently dangerous about DNA collection that is not the same as fingerprinting.

MR. SHANMUGAM: Well, there is, ... . [W]e certainly believe that there are profound privacy concerns associated with the government's collection of an individual's DNA. And leaving aside the question of how much personal information is contained in the 13 loci — and we certainly think that there is significant personal information even as to those loci — I don't think there can be any dispute that when you evaluate the entirety of an individual's DNA, there is a great deal of personal information contained there. And in our view, that has to be taken into account when engaging in balancing.

Cross-posted to The Double Helix Law Blog.

Sunday, March 3, 2013

The Oral Argument in Maryland v. King — Part II

As noted yesterday, the argument that DNA profiling and database trawling for past crimes is or will be useful for pretrial release determinations intrigued several of the Justices. Justice Sotomayor spoke up:
JUSTICE SOTOMAYOR: And I'm having a hard time understanding the bail argument.Because in my time, most bail decisions were made at the time of arrest. And here the arrest was in April and the results didn't come up until August. ... You don't use it routinely for the bail determination.

MS. WINFREE: At this point, you're absolutely correct, Justice Sotomayor. We don't use it routinely for a couple of reasons. For one, as in Mr. King's case, there has been in the past a more substantial delay in getting those results back. Our — our lab now is getting results between 11 and 17 days. ... Now, of course, that wouldn't be timely for that first bail determination, but the State under Maryland's procedure certainly has the ability to go back to — to the judge and ask that ... that bail determination to be modified. And in point of fact, ... in California's amicus brief, which was joined by the 49 other States and D.C. and Puerto Rico, they actually do cite two particular examples where [release or] diversion was revoked . ...
The Deputy Solicitor General maintained that this use of the DNA would only grow:
MR. DREEBEN: [R]apid DNA will permit DNA identification to replace fingerprint identification because it's far more accurate and it has far more utility in the secondary purpose of fingerprints, which is to match them to latent prints and solve crimes. ... Any judge who is looking at a bail case would like to know: I have a guy who has been arrested on grand theft auto. He has no criminal history. Should I release him back on the street? Well, it's a first offense, he has family ties; maybe yes. If that ... defendant's DNA came back and returned a cold case hit to a murder-rape, the judge would know he's not such a good risk to be put back on the street.* [* Order of clause rearranged.]
In responding to this argument, counsel for Mr. King first seemed to concede that when DNA profiling and database trawling could be done rapidly, the system would become constitutional:
CHIEF JUSTICE ROBERTS: There are two different, two different interests. One is we want to solve unsolved crimes; and the other is we want to be sure — we have someone in our custody and we want to be sure, before he is released back into the community, that he isn't a person who has committed five violent crimes before that. Now, your brief says, well, the only interest here is the law enforcement interest. And I found that persuasive because of the concern that it's going to take months to get the DNA back anyway, so they are going to have to release him or not before they know it. But if we are in a position where it now takes 90 minutes or will soon take 90 minutes to get the information back, I think that's entirely different, because there you can find out whether — it's just tied in with the bail situation, do you want to release him or not.

MR. SHANMUGAM: The touchstone of the analysis under the special needs doctrine is what was the primary purpose of the program at issue. And there is no evidence that pretrial supervision was a purpose of any of these.

CHIEF JUSTICE ROBERTS: That's because, that's because we are not yet at a situation where it takes 90 minutes. Sure, it's not going to do you any good if it's taking four months or whatever it took in this case. But if it's at the point where it's 90 minutes, it would be critical to make that determination.

MR. SHANMUGAM: Well, Mr. Chief Justice, ... the constitutional analysis may very well change at a later point. But I think it's important to underscore that neither the State of Maryland nor the federal government identifies a single instance in which a pretrial supervision decision in their jurisdictions was altered as a result of the DNA test.
But a little later he qualified his position:
JUSTICE SOTOMAYOR: Counsel, so I am really worried about the question ... that I think one of my colleagues asked. I agree completely that today it's used primarily and almost exclusively for purposes of solving other crimes.* But let's — is this — the question only because technology hasn't moved fast enough? You said we have to look at the constitutional principles 5 years from now when they will use it to pull up a guy's criminal history. Not unsolved crimes, but criminal history. Get to that day. ... Tell me what the — why you would then say that would still be unconstitutional. [* Order and wording of sentences altered slightly.]

MR. SHANMUGAM: Justice Sotomayor, ... the only other potentially applicable exception to the principle that warrantless, suspicionless searches are unconstitutional is the special needs exception, and that exception looks to the primary purpose of the program at issue. And the mere fact that DNA testing could be used for other purposes wouldn't necessarily be dispositive of the inquiry. If the primary purpose of DNA testing is still to investigate unsolved crimes, the program would still not qualify under the special needs doctrine.
Then again, under questioning from Justice Kagan, he conceded that the multipurpose system could be constitutional:
JUSTICE KAGAN: Just suppose — I mean, I guess the question is, would this be unconstitutional? It's not the world we are living in now, but let me — 10 years from now the government says, we are really switching over to a fingerprint system — to a DNA system and what that system is going to allow us to do, is it's going to allow us to identify, and it's going to allow us to bring up the old criminal history and it's going to allow us to see whether there are also unsolved crimes that we can tag to this person and discover that he's really, really dangerous. All right? And so the government puts that system into effect. Is it constitutional?

MR. SHANMUGAM: I think that it could be, and that would simply be because you would have a system where DNA testing is essentially being used as fingerprinting is being used today. But again I don't think —
The difficulty the Justices experienced in receiving a definitive response to their vision of a multipurpose DNA database system exposes part of the soft underbelly of the so-called special needs doctrine. One might well ask why “the primary purpose” of a program that produces evidence for criminal investigations and prosecutions is so critical? And, if it is so crucial, may a state salvage a law struck down as unconstitutional (because it was intended and used only to generate evidence in unrelated matters against mere arrestees) by re-enacting it, continuing to use it for its previous primary purpose of generating evidence, adding a new statutory preamble, and also using it (like fingerprints) for one or more additional purposes (such as gathering appropriate information for a bail determination) proclaimed in a carefully crafted preamble?

I asked these questions 13 years ago (Kaye 2001). The so-called special needs exception to the ordinary requirements of probable cause and a warrant applies when the government can articulate special interests in a program that also generates evidence of wrongdoing. For example, the government’s special interest in jail security and inmate health and safety justifies most of the searches that the Deputy Solicitor General reminded the Court about in the opening of his argument. When the government’s sole interest is producing evidence with which to catch criminals and the search is a significant intrusion of persons, houses, papers, or effects, then the normal rule is that warrants and probable cause are required. This reflects a prior balancing of governmental and personal interests that allows some searches but constrains arbitrary or unjustified government action. When special interests are present, however, the prior balancing is incomplete, and the outcome of a more comprehensive balancing could be different, As a result, the normal rule demanding warrants and probable cause might not apply (Kaye 2013).

Under this “special interests” theory, balancing is appropriate whenever special interests are present, and whether the balance of interests favors the government or individual does not depend on whether evidence production is a primary, secondary, or tertiary purpose of the program of searches. Yet, since 2000, the “special needs” doctrine has been more complicated—and less coherent than the reconstruction sketched above. As King argued, special interests do not trigger balancing unless they are the “primary purpose” of the program.

At least, this is what the Court first announced in City of Indianapolis v. Edmond, 531 U.S. 32 (2000). However. Edmond was not a multiple-purpose case. For the single purpose of finding narcotics in vehicles, Indianapolis established a program in which police used dogs to sniff for drugs in vehicles pulled over in groups at fixed roadblocks. The Court previously had upheld brief, suspicionless seizures at highway checkpoints for the such singular purposes as combating drunk driving and intercepting illegal immigrants. In addition, it had ruled that walking a drug-sniffing dog around a properly seized vehicle was not even a search. Thus, both components of the program—the checkpoints and the dog sniffs—had withstood constitutional attack. Yet, the Edmond majority reasoned that these cases did not govern: "Because the primary purpose of the Indianapolis narcotics checkpoint program is to uncover evidence of ordinary criminal wrongdoing,” the special needs exception was unavailable.

But neither Edmond nor any other case has tried to apply the primary-purpose limitation to a program that plausibly serves two or more purposes. Would the Indianapolis program have been eligible for special-needs balancing had the city established roadblocks strictly to check for intoxicated drivers, and then, after waiting a decent interval, added a dog-sniff in parallel with the sobriety check?

To cope with the analogous situation envisioned in the questions from the Chief Justice and Justices Kagan and Sotomayor, the Court has at least two stark choices. It could overrule Edmond and abandon the primary-purpose restriction, allowing special needs balancing as long as special interests actually are present. Or, it could engage in a slightly mystical search for the “primary” purpose of a truly multipurpose program.

But even if the special needs exception would apply in the future, the Chief Justice asked, what does it mean for the Maryland law today?
CHIEF JUSTICE ROBERTS: How can I base a decision today on what you tell me is going to happen in two years? You say, in two years we will have this rapid DNA available, but we don't now. Don't I have to base a decision on what we have today?

MS. WINFREE: Well, that's really only one component of our argument, Mr. Chief Justice, that certainly with respect to a bail determination we will be able to make it more rapidly at the time that rapid DNA comes into effect.
Whereupon Justice Scalia got in the last word during Maryland’s rebuttal argument. Expressing his reticence to uphold the Maryland program because of what it might become, he stated:
JUSTICE SCALIA: Yes, but if we believe that the purpose of it has much to do with whether it's legitimate or not, you can't demonstrate that the purpose is immediate identification of the people coming into custody. You just can't demonstrate that now. Maybe you can in two years. The purpose now is — is the purpose you began your presentation with, to catch the bad guys, which is a good thing. But you know, the Fourth Amendment sometimes stands in the way.

Saturday, March 2, 2013

The Oral Argument in Maryland v. King — Part I

Oral argument before the Supreme Court in Maryland v. King took place on Tuesday, Feb. 26.1/ Alonzo King, Jr., had been arrested in 2009, then charged and convicted of an assault. A Maryland law requires defendants charged with certain crimes to provide a DNA sample—before they are even tried. On this basis, King’s identifying DNA profile was obtained and included in a database of DNA profiles from arrestees and convicts, to be checked periodically against DNA profiles recovered from crime scenes.

King’s DNA profile played no role in the assault case. The state did not want it for that prosecution. Rather, it wanted to see if his DNA might connect him to some unsolved crime. Sure enough, it linked him to an unsolved 2003 rape of a 52-year-old woman. In the ensuing trial for that crime, the state proved that King, then 19 and wearing a mask, broke down the door, held a gun to the woman's head and sexually assaulted her. He was sentenced to life in prison.

The question before the Supreme Court was whether the state’s law mandating routine DNA sampling before conviction violates the Fourth Amendment’s protection against unreasonable searches or seizures.

I had the worst seat in the house — a small wooden chair against the far wall behind the farthest row of permanent seats. That hardly mattered. From any distance,  the argument would have appeared kaleidoscopic, with patterns forming and shifting apparently at random. Nevertheless, one major theme emerged from the questions: Is the rationale for upholding Maryland’s law confined to arrestees? Several Justices clearly were concerned that upholding this law would permit states or the federal government to acquire the DNA of everyone.

The Chief Justice introduced this line of questioning earlier in the argument for the state:
CHIEF JUSTICE ROBERTS: Your procedure limits the collection to certain violent offenses, right?

MS. WINFREE: It does, Mr. Chief Justice.

CHIEF JUSTICE ROBERTS: But your argument would not be so limited, would it? Under your theory, there's no reason you couldn't undertake this procedure with respect to anybody pulled over for a traffic violation?

MS. WINFREE: Well, in Maryland, it's not just the fact that we have those — those violent crimes and burglaries. Actually, we don't collect DNA unless someone is physically taken into custody. Now, with respect to —

CHIEF JUSTICE ROBERTS: Well, I understand. But there's no reason you couldn't, right? I gather it's not that hard. Police officers who give Breathalyzer tests, they can also take a Q-tip or whatever and get a DNA sample, right?

MS. WINFREE: Well, what I would say to that is that with respect to a traffic stop, this Court said in Berkheimer that a motorist has an expectation that a traffic stop is going to be relatively brief and temporary, that he or she will be given a citation and sent on their way.

CHIEF JUSTICE ROBERTS: Well, how long does it take to — to undergo the procedure? You say, ah and then —

MS. WINFREE: It doesn't take long, but what I was suggesting is that because of the nature of a traffic stop, this Court might well decide that a motorist has a reasonable expectation of privacy not to —
These answers are unsatisfying. In Illinois v. Caballes, 543 U.S. 405 (2005), the Court deemed the nature of a traffic stop irrelevant to the reasonableness of a search for something unrelated to the stop. Specifically, the Court rejected the argument that walking a drug sniffing dog around a car while an officer wrote the citation “converted the citizen-police encounter from a lawful traffic stop into a drug investigation, and because the shift in purpose was not supported by any reasonable suspicion that respondent possessed narcotics, it was unlawful.” Given that “governmental conduct that only reveals the possession of contraband ‘compromises no legitimate privacy interest,’” the Court concluded that the dog-sniff was not itself a search, and the traffic offense fully justified the temporary restraint on the driver’s freedom to travel was fully justified.

Rather than “the nature of the traffic stop” creating a reasonable expectation of privacy that would make the traffic-stop DNA sampling a search, it is the nature of DNA sampling (as currently conducted) that has this effect. Justice Scalia emphasized this when he later commented:
If there's no reasonable expectation of privacy, there's no search. But here, there is a search. You have a physical intrusion. You — you pull a guy's cheek apart and stick a — a swab into his mouth. That's a search — a reasonable expectation of privacy or not. 2/
Soon afterward, Maryland’s Chief Deputy Attorney General took another stab at explaining why its justifications for the law would not subject everyone to compulsory DNA sampling:
MS. WINFREE: Well, happily we don't have to decide that one today. But what I — the cornerstone of our argument is that when an individual is taken into custody, an individual is arrested on a probable cause, on a probable cause arrest, that person by virtue of being in that class of individuals whose conduct has led the police to arrest him on — based on probable cause surrenders a substantial amount of liberty and privacy.
The U.S. Department of Justice’s Deputy Solicitor General elaborated at the outset of his presentation:
MR. DREEBEN: Thank you, Mr. Chief Justice, and may it please the Court: Arrestees are in a unique category, they are on the gateway into the criminal justice system.    They are no longer like free citizens who are wandering around on the streets retaining full impact Fourth Amendment rights. The arrest itself substantially reduces the individual's expectation of privacy. The arrestee can be searched and sent to arrest. His property, whether or not connected with a crime, can be inventoried. When he's taken into the jail situation, he can be subjected to a visual strip search. If he's admitted to the population of the jail, he'll be given a TB test and a thorough medical screen. These are not individuals who are like free citizens, and they are not like free citizens in another significant respect. Arrestees are rarely arrested for the first time. They tend to be repeat customers in the criminal justice system. Up to 70 percent of arrestees have been previously arrested.
The trouble with this argument should be obvious. Of course, arrestees have been arrested and may be searched in ways inapplicable (thankfully) to people who not currently in police custody. But the fact that “they are not like free citizens” does not necessarily mean that the justifications for taking their DNA are not just as powerful when applied to the general population. One must go beyond diffuse talk of surrendering “a substantial amount of liberty and privacy” to adequately distinguish this group from the general population for the purpose of DNA identification testing. The argument that arrestees are different just because they have been arrested (and are likely to be re-arrested) is empty.

One thing that gives the difference claim some content is the state’s argument that DNA databases do or can provide significant information for pretrial supervision of arrestees. Much of the hour’s argument focused on Maryland’s contention that the “purpose of the statute is to enable the state to identify perpetrators of serious crimes and — and to use the information to make bail determinations for people who are validly in their custody.” Part II of this series will describe the Justices’ often skeptical questioning on this point.


1. For the same-day transcript, see

2. On its face, this comment seems to be internally inconsistent. The first sentence asserts that there can be no search without a reasonable expectation of privacy. The third says that is a search even if there is a reasonable expectation of privacy. I take it that Justice Scalia means that one need not fuss with reasonable-expectation test when there is a traditional trespass to gather information. This was the position that the Justice articulated for a majority of the Court in United States v. Jones, 132 S.Ct. 945 (2012).