Sunday, July 20, 2014

Stopping a Defendant from Using a DNA Database Trawl to Blame Someone Else in Diggs v. State

A violent burglary and robbery of two unsavory characters in their apartment near Rockville, Maryland, led to felony charges against two men, Allen and Diggs. Near the apartment, police recovered various items that seemed to be associated with the robbery. These included a Pittsburgh Pirates baseball hat and a black bandana that the robbers apparently had worn.

At their trial, Allen and Diggs called a single witness—“Naomi Strickman—a forensic specialist with the Montgomery County Crime Laboratory” to prove that a database search linked the DNA on these items to two other men named Bangora and Debreau. The prosecutor successfully objected that a Maryland statute made the database matches inadmissible.1 In Diggs v. State,2 the Maryland Special Court of Appeals affirmed and upheld the convictions.3 It endorsed the prosecution's reading of the statute's exclusionary rule.

But was the statute really designed to exclude a defendant’s evidence that a DNA database trawl produced other possible suspects? The statute provides that “[a] match obtained between an evidence sample and a data base entry may be used only as probable cause and is not admissible at trial unless confirmed by additional testing.”

This “additional testing” is not necessarily any different or any more accurate than the original testing. It normally consists of replicating the match to the crime-scene evidence with the same technology (or perhaps a more efficient variation on it) applied to a fresh DNA sample from the individual whose recorded profile matched. Such retesting is useful because it establishes that there was no bookkeeping error in entering the DNA record into the database and no laboratory error in determining the recorded profile. Checking the database match with a fresh sample is easily done, because the database match supplies probable cause to obtain the new sample and thereby verify that the profile on record really came from the individual whose name is on the record.4

If the state can rely on the database evidence for probable cause before trial, why cannot the defense rely on it for the same inference at trial? The court’s answer is “plain meaning.” The statute says “not admissible at trial” rather than “not admissible at trial when introduced by the prosecution.” But if the statute’s purpose is to avoid a conviction based on a clerical or laboratory error that can be easily caught by requiring the prosecution to confirm the database match, it is not so plain that it also was meant to force defendants to collect fresh DNA samples from people the state believes are innocent and test them to check the state’s work.

The Diggs court assumed that the dominant purpose of the provision is to ensure that the state uses “the most recent scientific and technological methodologies available” at trial. For some reason, the court thought that the confirmatory test is needed to produce further individualizing information, changing what was a mere probability to a near certainty. Judge Kehoe wrote that
A CODIS match probably, but does not always, mean that the two DNA samples represented by the DNA records came from the same person. ... [A]dditional analysis and testing is then completed on the DNA samples in order to determine whether the physical samples, themselves, “match”—i.e., whether, after the physical samples have been tested, compared, and analyzed, they are verified (to a near certain degree) to be from the same person.
But the statute does not mandate more extensive testing. It applies before any new equipment or procedures come on line. And, even if the state has a newer set of loci or fancier machinery, the words of the statute do not stop a state from using the older technology to confirm the database match.

Of course, it is possible that the confirmatory testing will include additional loci, but a 13-locus match is quite powerful evidence. For many years, it has been more than enough to seal the fates of thousands of defendants. Surely exculpatory evidence from the defense need not be more probative than that. Indeed, evidence that only generates “probable cause” to believe that someone else is responsible for the crime should be enough to inject a reasonable doubt into the proceedings.

Ignoring this asymmetry in the criminal process, the court asserts that the legislature's original intent was not just to ensure that before the state tries a defendant located through a database trawl, it checks that the database match was accurate. Displaying a certain suspicion of the third-party defense, the court attributes to the legislature an intent to render evidence inadmissible “at trial by a defendant as a mechanism to mislead, confuse, or otherwise distract the jury” .

However, a statutory exclusionary rule intended to protect defendants from false database matches is unnecessary to handle abuses of the third-party defense. The normal rules of evidence give the trial judge ample discretion to exclude testimony when there is so little substance to the defense theory that dragging innocent people whose DNA was in the database into the case would be unduly time-consuming and distracting. Interpreting the Maryland statute to encompass the defensive use of DNA database matches is unnecessary to protect against jury confusion or distraction. If the DNA evidence meets the ordinary standards of relevance and scientific validity, it should be admissible.

  1. Md. Code Ann. Public Safety § 2–510 (2003, 2009 Supp.).
  2. 73 A.3d 306 (Md. Ct. Spec. App. 2013).
  3. The opinion contains a meandering description of forensic DNA evidence. Although mitochondrial DNA has nothing to do with the case, the opinion launches into a discussion of mitochondrial testing. Among other things, it states that
    Human cells contain two genes capable of being analyzed for DNA: mitochondrial DNA (mtDNA) and nuclear DNA (nDNA). ... Mitochondrial DNA is the smaller of the DNA genes and is found within an organelle called the mitochondrion which floats “in the cytoplasm surrounding the nucleus of a cell.” ... Nuclear DNA is the larger of the DNA genes.
  4. The names are actually stored separately to protect the privacy of the individuals whose DNA is in the databank.

Saturday, July 19, 2014

Judge Richard Posner on DNA Evidence: Missing the Trees for the Forest?

In the cornucopia of court opinions, errors in the description of statistical concepts are a dime a dozen. Most never see the light of day. In a recent essay in Jurimetrics Journal, however, Northwestern University Law Professor Jay Koehler illuminated a few in an essay entitled “Forensic Fallacies and a Famous Judge.” 1/

The judge is Richard Posner of the U.S. Court of Appeals for the Seventh Circuit. At roughly the same time that Koehler’s essay appeared, the ABA's flagstaff magazine showcased Judge Posner as as “a prolific author whose seemingly endless curriculum vitae includes books on topics as varied as the economic basis of justice, intelligence reform, Bush v. Gore, the failures of capitalism, the Clinton impeachment, law in literature, antitrust theory, disaster response and the origins of nude dancing. ... a restless and engaged public intellectual.” (The ABA Journal’s interesting interview with him that followed these remarks is available online.)

Judge Posner's days as a professor at the University of Chicago Law School also made him a legendary figure in the law-and-economics movement, and Koehler identifies him as “a brilliant, quantitatively minded jurist ... the most-cited legal scholar in the world.” So what kinds of errors did this famous judge make?

You will have to read Koehler’s essay for his full answer. Here, I elaborate on, and supply additional criticism (along with some defense) of one passage from the opinion in United States v. Ford. 2/  The defendant in the case, John Ford, had been convicted of bank robbery before. Northwestern Law School’s Appellate Advocacy Center represented him on appeal from this second conviction. The Center convinced the Seventh Circuit panel that the photo spread shown the bank manager was so suggestive that his identification of the mug shot of Ford as the armed robber may well have violated due process. Despite this error, the Court of Appeals did not reverse the conviction. Sua sponte, the panel affirmed on the ground that the error was harmless.

It was harmless, in the court’s view, because other evidence was overwhelming. The other evidence was “the bank manager's description of the robber,” who wore “a dust mask that covered his nose and mouth,” together with proof “that the dust mask found outside the bank was the robber's, and the DNA found on the dust mask matched the defendant's DNA.” 3/

In explaining this harmless-error analysis, Judge Posner wrote:
Although the defendant's lawyer tried to throw dust in the jurors' eyes by a vigorous challenge to the DNA evidence, and might have succeeded with another jury, the challenge had no merit. What is involved, very simply, in forensic DNA analysis is comparing a strand of DNA (the genetic code) from the suspect with a strand of DNA found at the crime scene. See "DNA Profiling," Wikipedia, (visited May 31, 2012). Comparisons are made at various locations on each strand. At each location there is an allele (a unique gene form). In one location, for example, the probability of a person's having a particular allele might be 7 percent, and in another 10 percent. Suppose that the suspect's DNA and the DNA at the crime scene contained the same alleles at each of the two locations. The probability that the DNA was someone else's would be 7 percent if the comparison were confined to the first location, but only .7 percent (7 percent of 10 percent) if the comparison were expanded to two locations, because the probabilities are independent. Suppose identical alleles were found at 10 locations, which is what happened in this case; the probability that two persons would have so many identical alleles, a probability that can be computed by multiplying together the probabilities of an identical allele at each location, becomes infinitesimally small — in fact 1 in 29 trillion, provided no other comparisons reveal that the alleles at the same location on the two strands of DNA are different. This is the same procedure used for determining the probability that a perfectly balanced coin flipped 10 times in a row will come up heads all 10 times. The probability is .510, which is less than 1 in 1000.

Because the DNA sample taken from the dust mask was incomplete, 10 was all the locations that could be profiled; but that was enough to enable a confident estimation (the 1 in 29 trillion) that the probability that DNA on the dust mask was not the defendant's was exceedingly slight. No evidence was presented to cast doubt on the validity of the DNA test conducted in this case or on the odds stated by the government's expert witness; nor did the cross-examination of the witness, though vigorous, undermine his testimony. The combination in this case of the unimpeached DNA evidence with the bank manager's description of the robber would have persuaded any reasonable jury beyond a reasonable doubt that the defendant was the robber. 4/
Professor Koehler only quotes the part of this discussion involving alleles with population frequencies of 7% and 10%. He observes that:
Judge Posner commits the source probability error. This error involves equating the random match probability (RMP) in DNA analysis with the probability that someone other than the matchee is the source of the matching DNA profile. Judge Posner commits this fallacy when he writes that “the probability that the DNA was someone else's would be 7 percent” in a situation where the suspect's DNA matches DNA found at a crime scene, and where both DNA profiles contain an allele that is common to 7% of the population. Posner's logical error is easily seen when one considers that if the probability that the DNA belongs to someone other than the defendant is 7%, then it would have to be the case that the probability that the DNA belongs to the defendant would have to be 93%. But is this right? It is not. By this logic, every person who shares this particular allele would have a 93% chance of being the source of the DNA in question. Because many people share this allele (for example, 7% of people in Chicago alone would include about 200,000 people), it obviously cannot be the case that each of 200,000 allele-matching Chicagoans has a 93% chance of being the source of the DNA sample in question. To be clear, the probability associated with a DNA match—even a very small probability such as one in one million or one in one billion—does not itself identify the probability that the matchee is or is not the source of a recovered DNA sample. This latter probability cannot be identified absent a fact finder's estimate of the “prior probability” (that is, before the DNA analysis) that the matchee is the source of the evidence. The prior probability depends on nonforensic factors including, but not limited to, the strength of the nonforensic evidence presented in the case (for example, eyewitness testimony, motive, and so forth). In other words, counterintuitive though it may seem, the results of a DNA analysis cannot be translated directly into a probability that someone is or is not the source of DNA evidence. Judge Posner is certainly not the only person who has failed to appreciate this point. Since the earliest days of DNA evidence, judges, attorneys, jurors and experts alike have been committing the source probability error. 5/
Professor Koehler is correct. For many decades Judges have been committing not only the “source probability error” for DNA and other forms of trace evidence 6/ but also the more general fallacy of the transposed conditional with p-values and confidence intervals. 7/ Judge Posner’s opinion is yet another instance. However, in some respects the passage is both more and less troubling than Koehler indicates.

The court’s description of its computation displays a certain ignorance of genetics of STRs (short tandem repeats) as well as a lack of precision in describing probabilities. First, the STR alleles are not “unique gene forms.” That is, they are not forms of genes, and no forensic STR allele is unique. Some STRs happen to lie within introns of genes, but even those alleles do not change the expressed proteins. Other courts of appeals use slightly better terminology in their opinions. 8/ One state court of appeals did a lot worse, writing that "Human cells contain two genes capable of being analyzed for DNA: mitochondrial DNA (mtDNA) and nuclear DNA (nDNA). We will take each of these genes in turn. ... Nuclear DNA is the larger of the DNA genes." 9/

Second, it is not “the probabilities” that “are independent.” It is the individual events whose unconditional probabilities are multiplied to arrive at the probability of a joint event (the profile) that are nearly independent.

Third, the profile probability is not just the product of the allele frequencies. Two alleles occur at each locus. If one allele (A) at a locus has a 7% population frequency and the other one (B) at that same locus has a 10% frequency, then the frequency of the combination is expected to be 2(.07×.10) = 1.4%, not .7%. (The multiple of 2 is necessary because the A could have come the father and the B from the mother or vice versa.) If only one peak (corresponding to A) appears at one locus and only one (B) appears at the other locus, then the two-locus probability is .072 × .102 = .0049%. (This assumes that both loci are homozygous—that both parents transmitted the same allele. If the peak heights are not consistent with this supposition and drop-out is suspected, a conservative calculation would be 2(.07×1) × 2(.10×1) = 2.8%.)

Of course, Judge Posner could respond by accusing Professor Koehler (and now me) of trying “to throw dust in the [readers'] eyes” or of missing the forest for the trees. To an extent, that response would be correct.

Sure, it would be nice if the Seventh Circuit could adhere to standard terminology in genetics and statistics, but none of these errors had an effect on the case. In Ford, a substantial fraction of the population could not reasonably be regarded as the source of the DNA on the dust mask. At least not if one believes that the random-match probability is p = 1/29,000,000,000,000. In that event, the probability of at least one unrelated individual in all of Chicago having matching DNA could be approximated as 1 – enp, where n is the Chicago population of about 2.7 million men, women, and children. This duplication probability is only 0.008%.

Well, what about a brother matching at these ten loci? A rough calculation (from the formula at page 87 of the 1992 NRC Committee report on forensic DNA technology) gives a full sibling match probability of about 0.001%.

In other words, Judge Posner’s linguistic or computational errors in describing DNA profiling are themselves harmless—in this case. But it would be unfortunate if other courts were to rely on the infelicitous phrasing in Ford, especially in cases in which the random-match probabilities are less extreme. It also would be dangerous to emulate the judge's reliance on Wikipedia for a understanding of forensic DNA evidence issues, but that's a complaint for another day.

  1. Jonathan J. Koehler, Forensic Fallacies and a Famous Judge, 54 Jurimetrics J. 211 (2014)
  2. 683 F.3d 761 (7th Cir. 2012).
  3. Id. at 767.
  4. Id. at 768.
  5. Koehler, supra note 1, at 215–16 (notes omitted).
  6. David H. Kaye, David E. Bernstein & Jennifer L. Mnookin, The Wigmore, A Treatise on Evidence: Expert Evidence § 14.1.2 (2d ed. 2011); 2014 Cumulative Supp. § 14.5.1(b).
  7. Id. §§ 12.8.2(b) , 12.8.3(a).
  8. E.g., United States v. Mitchell, 652 F. 3d 387, 400 (3rd Cir. 2011) ("non-genic stretches of DNA not presently recognized as being responsible for trait coding") (quoting United States v. Kincade, 379 F.3d 813, 818 (9th Cir.2004) (en banc) (plurality opinion).
  9. Diggs v. State, 73 A.3d 306, 317-18 (Md. Ct. Spec. App. 2013).

Thursday, July 17, 2014

The Constitutionality of DNA Collection Before Conviction: An Updated Scorecard

Note: This posting updates previous ones. It is current as of July 17, 2014.

Seventeen years ago, Louisiana adopted a law mandating that "[a] person who is arrested for a felony sex offense or other specified offense . . . shall have a DNA sample drawn or taken at the same time he is fingerprinted pursuant to the booking procedure." As of mid-2012, 28 states and the federal government had laws providing for DNA sampling before any conviction is obtained. Most other countries with DNA databases also collect samples on arrest.

The DNA-before-conviction (DNA-BC) laws in the U.S. had a placid childhood, with surprisingly few challenges to their constitutionality. In contrast to their older brother, laws mandating DNA collection after conviction (DNA-AC), which were upheld in scores of cases, DNA-BC laws provoked conflicting constitutional opinions.

In June 2013, after years of declining to review opinions on the constitutionality of DNA databases, the Supreme Court stepped in to decide whether the Maryland Court of Appeal erred in holding that collecting DNA samples as part of the booking process violated the Fourth Amendment.A sharply dividing Court held that Maryland's system of DNA sampling, testing, and database searching was not an unreasonable search under the Fourth Amendment.

This posting presents a scoreboard on the litigation and scholarly commentary to date. If any players or contests have been omitted, I hope that readers will correct those omissions by leaving a comment. The law review articles listed in the table do not include ones on DNA-AC. Authors who have contended that these databases are unconstitutional would reach the same conclusion for a database that includes arrestees, but the lower courts have resoundingly rejected their analyses. Therefore, little would be gained by keeping track of the many articles on convicted-offender databases.

The tables indicate that before the Supreme Court's opinion in Maryland v. King, there was no clear consensus among lower courts on the constitutionality of taking DNA samples during a custodial arrest (or at another point before conviction) with the intention of running database searches (in the absence of a warrant and probable cause to believe that the search will produce a hit in the database).

The Supreme Court's decision in King has not ended all constitutional challenges to DNA database laws. The lingering litigation concerns arguable distinctions between Maryland's statute and those of other jurisdictions and the effect of state constitutional provisions.

Table 1. Case law

Appellate: Supreme Court of the United States
  • Maryland v. King, 133 S. Ct. 1958 (2013) (state law requiring testing after arraignment constitutional under totality-of-the-circumstances balancing test)
Appellate: State Supreme Courts (1.5-2.5)
  • Mario W. v. Kaipio, Commissioner, 281 P.3d 476 (Ariz. 2012) (state arrestee law for juveniles constitutional insofar as it allows sampling as a booking procedure, but pre-conviction analysis of the sample is unconstitutional under a totality-of-the-circumstances standard and an analogy to searching containers)
  • King v. State, 42 A.3d 549 (Md. 2012) (state law requiring testing after arraignment unconstitutional "as applied" under a totality-of-the-circumstances balancing test), rev'd sub nom. Maryland v. King, 133 S. Ct. 1958 (2013)
  • Anderson v. Commonwealth, 650 S.E.2d 702 (Va. 2007) (state law constitutional under unspecified balancing test and analogy to fingerprinting as a booking procedure)
  • State v. Medina, 2014 VT 69 (state law violates state constitution under a restricted version of the special-needs balancing test)
  • Related case: State v. Franklin, 76 So.3d 423 (La. 2011) (no search warrant required to take a DNA sample from a murder defendant for use in the murder investigation because he had to submit a sample "as a routine incident of booking" anyway)
Appellate: State Intermediate Courts (opinions not reviewed by higher courts) (2-2)
  • People v. Buza, 197 Cal.App.4th 1424 (Cal. Ct. App. 2011) (state law unconstitutional under balancing tests), rev. granted, 262 P.3d 854 (Cal. 2011), vacated and remanded for reconsideration in light of Maryland v. King, 302 P.3d 1051 (Cal. 2013)
  • People v. Lowe, 165 Cal.Rptr.3d 107 (Cal. Ct. App. 2013) (state law constitutional under "totality" balancing test), rev. granted, 320 P.3d 799 (Cal. 2014)
  • State v. Biery, 318 P.3d 1020, 2014 WL 802100 (Kan. Ct. App. 2014) (unpublished) (state law constitutional under Fourth Amendment as construed in Maryland v. King and under state constitution)
  • In re Welfare of C.T.L., 722 N.W.2d 484 (Minn. Ct. App. 2006) (state arrestee law unconstitutional as per se unreasonable without probable cause and a warrant)
Appellate: Federal Courts (3-0)
  • United States v. Mitchell, 652 F.3d 387 (3d Cir. 2011) (en banc) (federal arrestee law constitutional under "totality of circumstances" balancing test)
  • Haskell v. Harris, 669 F.3d 1049 (9th Cir. 2012) (state arrestee law constitutional under totality-of-the-circumstances balancing test), vacated by grant of rehearing en banc, 686 F. 3d 1121 (9th Cir. 2012), aff'd as to denial of preliminary injunction, 745 F. 3d 1269 (9th Cir. 2014) (en banc)
  • United States v. Pool, 621 F.3d 1213 (9th Cir. 2010) (federal arrestee law constitutional under "totality of circumstances" balancing test), vacated as moot, 659 F.3d 761 (9th Cir. 2011) (en banc)
  • Related case: Friedman v. Boucher, 580 F.3d 847 (9th Cir. 2009) (an arrest does not justify DNA sampling without an applicable statute)
Trial Courts: Federal (not reviewed by higher courts) (4-1)
  • United States v. Thomas, No. 10-CR-6172 CJS, 2011 WL 1627321 (W.D.N.Y. Apr. 27, 2011) (federal arrestee law constitutional under "special needs" balancing test), dismissed, No. 11-1742 (2d Cir. Sept. 20, 2011), ECF No. 43
  • United States v. Demasi, Crim. No. 12–197, 2013 WL 24818 (W.D.Pa. Jan. 2, 2013) (federal  law constitutional applying Mitchell)
  • United States v. Robinette, No. 13–CR–0003 AWI BAM, 2013 WL 211112 (E.D.Cal. Jan. 18, 2013) (federal law constitutional at least until the Supreme Court rules in King v. Maryland)
  • Amended Order Denying the Government's Motion to Compel DNA Samples, United States v. Frank, No. CR-092075-EFS-1(E.D. Wash. Mar. 10, 2010), available at (applying totality balancing to a limited list of interests to find compulsory collection before conviction unconstitutional)
  • United States v. Fricosu, No. 10-cr-00509-REB-01 (D. Colo. Feb. 22, 2012) (federal law constitutional under totality standard), available at
  • Related case: United States v. Purdy, No. 8:05CR204, 2005 WL 3465721 (D. Neb. 2005) (forcibly taking a buccal swab from an arrestee violates Fourth Amendment in the absence of a statute providing for a uniform and limited system of sampling)
Trial Courts: Federal (reviewed by higher courts) (2-1)
  • United States v. Mitchell, 681 F.Supp.2d 597 (W.D.Pa. 2009) (federal law held unconstitutional), rev'd, 652 F.3d 387 (3d Cir. 2011) (en banc)
  • United States v. Pool, 645 F.Supp.2d 903 (E.D.Cal. 2009) (federal arrestee law constitutional under "totality of circumstances" balancing test), aff'd, 621 F.3d 1213 (9th Cir. 2010), affirming opinion vacated as moot, 659 F.3d 761 (9th Cir. 2011) (en banc)
  • Haskell v. Brown, 677 F.Supp.2d 1187 (N.D. Cal. 2009) (denying a preliminary injunction against the enforcement of California's arrestee sampling law in large part because the balance of interests establishes that the requirement is constitutional), aff'd sub nom. Haskell v. Harris, 669 F.3d 1049 (9th Cir.), reh'g en banc granted, 686 F.3d 1121 (9th Cir. 2012), aff'd, 745 F. 3d 1269 (9th Cir. 2014) (en banc)

Table 2. Law Review Articles and Notes
Faculty and Professional Authors
  • D.H. Kaye, The Constitutionality of DNA Sampling on Arrest, 10 Cornell J.L. & Pub. Pol'y 455-508 (2001) (a statute with sufficient protections to confine the government to identifying information is constitutional under the special needs exception)
  • Tracey Maclin, Is Obtaining an Arrestee's DNA a Valid Special Needs Search Under the Fourth Amendment? What Should (and Will) the Supreme Court Do?, 34 J.L. Med. & Ethics 165, 178-82 (2006) (predicting that the Supreme Court will uphold taking DNA from arrestees under a balancing test but stating that it should reject the practice as per se unreasonable)
  • D. H. Kaye, Who Needs Special Needs? On the Constitutionality of Collecting DNA and Other Biometric Data from Arrestees, 34 J.L. Med. & Ethics 188 (2006) (proposing a "biometric information exception" to the warrant requirement)
  • Brian Gallini, Step Out of the Car: License, Registration, and DNA Please, 62 Ark. L. Rev. 475 (2009) (Arkansas law unconstitutional because it does not require a judicial finding of probable cause arrest, contains inadequate safeguards to protect the samples and records, and because it does not fall within an established exception to the warrant requirement)
  • Kevin Lapp & Joy Radice, A Better Balancing: Reconsidering Pre-Conviction DNA Extraction from Federal Arrestees, 90 N. Car. L. Rev. Addendum 157 (2012) (pre-conviction DNA extraction should be permitted only after a neutral third-party finding of probable cause and DNA samples should be destroyed)
  • David H. Kaye, Drawing Lines: Unrelated Probable Cause as a Prerequisite to Early DNA Collection, 91 N.C. L. Rev. Addendum 1 (2012) (a formal finding of probable cause for an unrelated arrest is not constitutionally required)
  • David H. Kaye, On the "Considered Analysis" of DNA Collection Before Conviction, 60 UCLA L. Rev. Discourse 104 (2013)
  • David H. Kaye, A Fourth Amendment Theory for Arrestee DNA and Other Biometric Databases, 15 U. Pa. J. Const. L.  1095 (2013)
  • Henry T. Greely & David H. Kaye, A Brief of Genetics, Genomics and Forensic Science Researchers in Maryland v. King, 54 Jurimetrics J. 43 (2013)
  • Elizabeth E. Joh, Maryland v. King: Policing and Genetic Privacy, 11 Ohio St. J. Crim. L. 281 (2013)
  • Andrea Roth, Maryland v. King and the Wonderful, Horrible DNA Revolution in Law Enforcement, 11 Ohio St. J. Crim. L. 295 (2013)
  • Erin Murphy, License, Registration, Cheek Swab: DNA Testing and the Divided Court, 127 Harv. L. Rev. 161 (2013)
  • David H. Kaye, Maryland v. King: Per Se Unreasonableness, the Golden Rule, and the Future of DNA Databases, 127 Harv. L. Rev. Forum 39 (2013)
  • Jessica D. Gabel, Indecent Exposure: Genes Are More than a Brand Name Label in the DNA Database Debate, 42 U. Balt. L. Rev. 561 (2013)
  • Rana Santos, Why DNA Databasing Is Good for Maryland: A DNA Analyst's Perspective, 42 U. Balt. L. Rev. 591 (2013)
  • Tracey Maclin, Maryland v. King: Terry v. Ohio Redux, 2013 Sup. Ct. Rev. 359
  • David H. Kaye, Why So Contrived? DNA Databases After Maryland v. King, 104 J. Crim. L. & Criminology (forthcoming Aug. 2014), draft available at 
  • Related article: Robert Molko, The Perils of Suspicionless DNA Extraction of Arrestees Under California Proposition 69: Liability of the California Prosecutor for Fourth Amendment Violation? The Uncertainty Continues in 2010, 37 W. St. U. L. Rev. 183 (2010) (reaching no conclusions)
  • Martha L. Lawson, Note, Personal Does Not Always Equal "Private": The Constitutionality of Requiring DNA Samples from Convicted Felons and Arrestees, 9 Wm. & Mary Bill Rts. J. 645 (2001) (the government's interest in mandatory testing of all those arrested outweighs individuals' privacy interests)
  • ReneĆ© A. Germaine, Comment, "You Have the Right to Remain Silent. . . You Have No Right to Your DNA" Louisiana's DNA Detection of Sexual and Violent Offender's Act: An Impermissible Infringement on Fourth Amendment Search and Seizure, 22 J. Marshall J. Computer Info. L. 759 (2004) (unconstitutional under balancing test other than special needs)
  • Kimberly A. Polanco, Note, Constitutional Law-The Fourth Amendment Challenge to DNA Sampling of Arrestees Pursuant to the Justice for All Act of 2004: A Proposed Modification to the Traditional Fourth Amendment Test of Reasonableness, 27 U. Ark. Little Rock L. Rev. 483 (2005) (constitutional under a balancing test)
  • Robert Berlet, Comment, A Step Too Far: Due Process and DNA Collection in California after Proposition 69, 40 U.C. Davis L. Rev. 1481 (2007) (with certain modifications, arrestee DNA sampling as provided for under California law would be constitutional)
  • John D. Biancamano, Note, Arresting DNA: The Evolving Nature of DNA Collection Statutes and Their Fourth Amendment Justifications, 70 Ohio St. L.J. 619 (2009) (unconstitutional under special needs and totality of the circumstances tests)
  • Corey Preston, Note, Faulty Foundations: How the False Analogy to Routine Fingerprinting Undermines the Argument for Arrestee DNA Sampling, 19 Wm. & Mary Bill Rts. J. 475 (2010)
  • Ashley Eiler, Note, Arrested Development: Reforming the Federal All-Arrestee DNA Collection Statute to Comply with the Fourth Amendment, 79 Geo. Wash. L.Rev. 1201, 1220 (2011)
  • Lauren N. Hobson, Note, North Carolina's Arrested Development: Fourth Amendment Problems in the DNA Database Act of 2010, 89 N.C. L. Rev. 1309 (2011) (unconstitutional because no existing exception to the Warrant Clause applies)
  • Kelly Ferrell, Comment, Twenty-first Century Surveillance: DNA “Data-mining” and the Erosion of the Fourth Amendment, 51 Hous. L. Rev. 229 (2013)
  • Alex Sugzda, Note, You're under Arrest-say Ah: Suggestions for Legislatures Drafting Statutes Allowing DNA Extraction from Arrestees, 70 Wash. & Lee L. Rev. 1443 (2013)
  • Jesika S. Wehunt, Note, Drawing the Line: DNA Databasing at Arrest and Sample Expungement, 29 Ga. St. U. L. Rev. 1063 (2013)
  • George M. Dery III, Opening One's Mouth “For Royal Inspection”: the Supreme Court Allows Collection of DNA from Felony Arrestees in Maryland v. King, 2 Va. J. Crim. L. 116 (2014)
  • Stephanie B. Noronha, Comment, Maryland v. King: Sacrificing the Fourth Amendment to Build up the DNA Database, 73 Md. L. Rev. 667 (2014)
  • Brian Clark Stuart, Comment, Dethroning King: Why the Warrantless DNA Testing of Arrestees Should Be Prohibited under State Constitutions, 83 Miss. L.J. 1111 (2014)
  • Related note: Jacqueline K. S. Lew, Note, The Next Step in DNA Databank Expansion? The Constitutionality of DNA Sampling of Former Arrestees, 57 Hastings L.J. 199 (2005) (unconstitutional as applied to "former arrestees")


Julie Samuels, Elizabeth Davies, Dwight Pope et al., Collecting DNA From Arrestees: Implementation Lessons, NIJ J., June 2012,

15 La . Rev. Stat. § 609(A)(1) ("A person who is arrested for a felony sex offense or other specified offense, including an attempt, conspiracy, criminal solicitation, or accessory after the fact of such offenses on or after September 1, 1999, shall have a DNA sample drawn or taken at the same time he is fingerprinted pursuant to the booking procedure."), derived from Act No. 737, approved July 9, 1997, and amended in 2003 (adding the phrase "including an attempt, conspiracy, criminal solicitation, or accessory after the fact of such offenses")

Wednesday, July 16, 2014

The Impact of Medina's Marginal Balancing on DNA Databases and Sample Retention

The opinion of the Supreme Court of Vermont in State v. Medina is a first. This is not because it strikes down a law requiring all individuals merely charged with felonies to submit to DNA sampling. Other state courts have held that state laws providing for DNA collection before conviction are unconstitutional. However, they reasoned that the prohibition on unreasonable searches and seizures in the Fourth Amendment to the U.S. Constitution compelled such action. The Vermont court relied entirely on a provision of the Vermont Constitution (Article 11).

Article 11 proclaims “That the people have a right to hold themselves, their houses, papers, and possessions, free from search or seizure.”  However, the Vermont Supreme Court has never taken this proclamation literally. Article 11 goes on to recognize that searches or seizures can proceed on the basis of “warrants ...  affording sufficient foundation,” and, as Medina noted, the Vermont Supreme Court has “import[ed]” into Article 11 “the ‘reasonableness’ criterion of the Fourth Amendment.”

But “reasonableness” does not usually entail a fact-specific balancing of individual and government interests. Indeed, this June, the Supreme Court disapproved of warrantless seizures and searches of cellphones notwithstanding the argument that they were just “incident to arrest.” In Riley v. California, the Court reiterated the rule that “[i]n the absence of a warrant, a search is reasonable only if it falls within a specific exception to the warrant requirement.”

So too, the Vermont court declared that under Article 11, “[w]arrantless searches are thus per se unreasonable” although “sometimes permitted.” And it pointed to its opinion in State v. Martin, a 2008 case upholding a post-conviction DNA database, on the theory “that using DNA to determine who committed a past crime is fulfilling an ordinary law enforcement purpose” but using it to link the same person to future crimes is a kind of “special need” for which a warrant is unnecessary as long as the state’s interests outweigh the convicted offender’s.

This is weird. Why should police have to get a warrant to search you when they suspect you of a past crime, but not when they think you might commit one in the future? Nevertheless, the Medina court used this distinction to apply a balancing test. That test, in the hands of Justice John Dooley and two justices who joined his opinion, had some unusual or questionable features.

First, it was a marginal balancing test. That is, the court asked how much extra future crime-fighting power taking DNA before conviction achieved. That is a sensible question for the legislature to weigh before enacting a DNA-on-arrest law (and to study later by having law enforcement agencies gather data on the efficacy of the law). But laws are often compromises, and it is almost always possible to envision less drastic alternatives. For example, a DNA-after-conviction law might include provisions for destroying most samples after the profiles are recorded or for deleting the profiles after a certain period of time. It might be restricted to adult offenders or to a smaller set of offenses. A strict less-drastic-alterative test could put the courts in the business of tweaking legislation. The U.S. Supreme Court has done so for the sake of protecting First Amendment rights but not Fourth Amendment ones.

Second, the Vermont balancing test considered some but not all of the state’s interests. Solving past crimes—through matches to DNA from old rape kits, for example—did not count. If one is going to balance at all, why not put all the relevant interests on the scale? To be sure, the standard interest in solving old crimes is not enough to overcome the individual interests in the security of the person in the absence of a well founded warrant. But that hardly means that it must be ignored when this categorical rule does not apply because the balance of all the state and individual interests may be different. 1/

Third, the majority used the fact that the statute required “expungement of the sample and profile when the adjudication is completed without a conviction of a qualifying crime” as a mark against it. According to these three justices, the legislature’s adoption of this less drastic alternative meant that it determined that it had less need for the samples from unconvicted suspects than from convicted ones. Does this mean that if the legislature re-enacts the law without providing for expungement, the case for upholding the law will be stronger? 2/

Fourth, on the individual side of the balance, Vermont’s justices believed that “each defendant’s privacy interest is greater [than it would be after a conviction] because he or she has not been convicted.” This is a mainstream view, but it seems like a category mistake. Why does your interest in personal security or privacy deserve less weight because you have been convicted of a crime? Certainly, the conviction can subject you to punishment—fines or imprisonment. But this is not because you have a lesser interest in retaining your money and your liberty than anyone else. The significance of the conviction is that the state’s general interests in deterrence, rehabilitation, or retribution carry more weight as applied to known offenders.

Fifth, the court rests its decision on the theory that “[t]he privacy interest of the preconviction defendant is greater than the interest of one who has been convicted because a preconviction defendant has a presumption of innocence.” But the legal presumption of innocence is an evidentiary doctrine that requires the state to prove guilt without relying on the fact that the defendant has been charged with the crime as if it indicates guilt. 3/  It has no bearing on the extent of any privacy interest. As we just noted, a conviction intensifies or focuses the state interests, permitting it to invade some privacy interests that it otherwise could not. Therefore, although the fact of a conviction is an important consideration in a reasonableness inquiry, the “presumption” adds nothing to the balancing test.

Sixth, Medina distinguished fingerprinting of arrestees from DNA sampling on two grounds. The majority thought that unlike DNA, “fingerprints can show only identification, and they have limited functionality in solving old cases.” These claims ignore the fact that fingerprint patterns are not without medical significance and that they routinely solve old cases. 4/ Just last year, the FBI’s criminal fingerprint database received hundreds of thousands of queries for possible matches to latent prints. Nonetheless, it is surely true that DNA samples contain far more socially and personally significant information than fingerprints. The response of most courts, and of course the U.S. Supreme Court in King, has been that statutory protections against accessing that kind of information are sufficient to satisfy a balancing test.

The Medina court disagreed. It stated that “[w]hile current law limits use of the sample, that law can be amended to allow greater use; the retention of the DNA sample suggests that expanded use is possible in the future.” But almost anything is possible in the future. Courts do not normally strike down otherwise constitutional laws because they might be amended in a manner that would make them unconstitutional.

If Vermont follows this unusual approach to constitutional analysis, its entire DNA database law might be unconstitutional under Article 11. Despite its effort to distinguish Martin, the earlier case on convicted-offender DNA collection, Medina observes that “Martin is silent on the storage of the sample, which is retained by the State, apparently indefinitely. ... Neither the statutory purposes, nor the State’s asserted justifications for the law, provide any rationale for retaining the DNA sample once the profile has been created.”

The majority apparently did not think that indefinite sample retention was so grave a risk to privacy as to invalidate the convicted-offender database system, but given the court's understanding of DNA databases, a stringent version of marginal balancing should have this effect. After all, if there is "no rationale" to retain samples indefinitely, and if the risk that the legislature will amend the law to permit the state to mine the samples for sensitive personal information is a weighty concern, there is no state interest to justify sample retention. Conversely, could the legislature revive the part of its law that the court struck down by providing for prompt destruction of those samples? At that point, what basis would the court have to insist that DNA identification is dramatically different from fingerprint identification?


1. See, e.g., David H. Kaye, Why So Contrived? DNA Databases After Maryland v. King, 104 J. Crim. L. & Criminology (forthcoming August 2014), early draft available at

2. Cf. David H. Kaye, Drawing Lines: Unrelated Probable Cause as a Prerequisite to Early DNA Collection, 91 N.C. L. Rev. Addendum 1 (2012),

3. David H. Kaye, A Fourth Amendment Theory for Arrestee DNA and Other Biometric Databases, 15 U. Pa. J. Const. L. 1095 (2013), available at; David H. Kaye, Associational Privacy, the Presumption of Innocence, and “Corruption of Blood” as Constitutional Metaphors in the Debate on “Familial Searching,” Amer. Crim. L. Rev. (Nov. 26, 2012),

Earlier Posting on State v. Medina

State v. Medina: Can the Vermont Supreme Court Overrule the U.S. Supreme Court on DNA Databases? July 11, 2014,

Friday, July 11, 2014

State v. Medina: Can the Vermont Supreme Court Overrule the U.S. Supreme Court on DNA Databases?

Today the Vermont Supreme Court struck down as unconstitutional Vermont’s law requiring individuals charged with any felony to submit to DNA sampling. The court reached this conclusion in a set of consolidated cases led by State v. Medina.

This outcome might seem surprising following the decision of the U.S. Supreme Court in Maryland v. King, 133 S. Ct. 1958 (2013) (discussed in many previous postings). After all, in King, the Court reversed the decision of Maryland’s highest court that a similar Maryland statute infringed an arrestee’s right to be free from unreasonable searches and seizures.

The Vermont court faces no risk of reversal, however, for its opinion relies strictly on the protection against searches and seizures in the Vermont Constitution. Article 11 of this state constitution provides
That the people have a right to hold themselves, their houses, papers, and possessions, free from search or seizure; and therefore warrants, without oath or affirmation first made, affording sufficient foundation for them, and whereby any officer or messenger may be commanded or required to search suspected places, or to seize any person or persons, his, her or their property, not particularly described, are contrary to that right, and ought not to be granted.

The U.S. Supreme Court is only supreme when it comes to federal law. A state normally is free to adopt a statute or to interpret its constitution so as to confer greater rights on its citizens that those recognized for everyone in the federal Constitution.  The Fourth Amendment to the U.S. Constitution declares that
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Thus, Maryland v. King merely held that the Maryland Court of Appeal erred in construing the Fourth Amendment to bar DNA sampling soon after arrests for certain felonies (because, given the state and individual interests affected, the DNA sampling was “reasonable”). Even though some of the same words appear in Vermont's Article 11, the Vermont Supreme Court has the power to interpret them differently.

Indeed, the Maryland Court of Appeal could turn around and invalidate the Maryland law notwithstanding the Supreme Court's opinion in King. Article 26 of the Maryland Constitution of 1867 specifies
That all warrants, without oath or affirmation, to search suspected places, or to seize any person or property, are grievous and oppressive; and all general warrants to search suspected places, or to apprehend suspected persons, without naming or describing the place, or the person in special, are illegal, and ought not to be granted.

A new arrestee in Maryland might argue that Maryland's statute requiring the seizure of DNA without an oath or affirmation setting forth probable cause and approved by a magistrate is tantamount to a proscribed “general warrant” or “grievous and oppressive.” Of course, this is essentially the argument that the Supreme Court rejected for the Fourth Amendment, but a state court can embrace such reasoning as applied to its state constitution.

And that is what the Vermont Supreme Court did today, by a vote of 3–2.

Coming up: Analysis of the reasoning in Medina.

Monday, July 7, 2014

McDaniel v. Brown: Whose Error?

The DNA analyst who miscomputed the siblingship probability and accepted the prosecutor's transposition of her random match probability in McDaniel v. Brown (discussed in the previous posting) now leads the Washoe County Sheriff’s Office Forensic Science Division. After the Ninth Circuit's ruling, she explained to a television news reporter that "the prosecutor ... led her through a complicated mathematical journey aimed at reducing Brown's guilt to a percentage." The mathematical journey, as recorded in the trial transcript (left panel), follows. Annotations are in the right panel.

Q [by the prosecutor]: Now, for my benefit, we're looking at a one in 3 million statistic, is there another way to show that statistic? In other words, what -- let's say 100 percent -- what is the likelihood that the DNA found in the panties is the same as the DNA found in the defendant's blood?
A: Paternity testing uses percentages.
Q: Okay.
A: Not the way forensics likes to look at it. We prefer the one in 3 million.
The probability of paternity in parentage testing is a posterior probability computed via Bayes' rule with hypothetical prior odds of 1. It is no more (or less) a percentage than is any other fractional quantity.
Q: I understand that, but for just another way to look at it, what would that percentage be?
A: It would be 99.99967 percent. That's what --
MR. SMITH: May I go to the blackboard, Judge?
THE COURT: Well, we'll pull it out for you and you want her to write on it?
MR. SMITH: No, I'd like to write on it.
THE COURT: Well, I don't think you're a witness. I'm not going to let you write on it now.
MR. SMITH: All right.
THE COURT: If you want her to write on it, she can write on it.
By MR. SMITH (continuing):
Q: Okay. If -- Ms. Romero, if you'd write it down, please.
A: Okay.
THE COURT: Is there a -- could you make the decimal a little bigger for us older --
By MR. SMITH (continuing):
Q: So, okay. So, if you would do, also, put 100 percent on top of that, if you would, please, with the corresponding number of zeros after the decimal point. And if you would please, then, subtract the lower number from the higher number.
A: I don't think this is right. Just a minute.
Q: All right. So, if you put a little line under the 99 there and a minus -- subtraction indication. All right. All right. Thank you. If you'd just take -- resume the stand.
Q: So, the -- would it be fair to say, based on that that the chances that the DNA found in the panties -- the semen in the panties -- and the blood sample, the likelihood that it is not Troy Brown would be .000033?
A: I'd prefer to refer to it as the one in 3 million.
Q: All right. But from a mathematical standpoint, would that be inaccurate?
A: Repeat the question, please.
Q: Would it be fair, then, to say that with that mathematical calculation there, that the likelihood that the DNA extracted from the semen in the panties and the DNA extracted from the blood that the likelihood that it's not Troy Brown, that it's not a match is .000033?
MR. LOCKIE: Your Honor, I'm going to object on relevance. The witness is testifying that it's not scientifically valid in her opinion. So it's not relevant.
THE COURT: Well, I don't know that --
MR. LOCKIE: That's just a subtraction problem.
THE COURT: Let's go back. I don't think that's what she said. I don't think that's what she said. Let's go back a step and find out. I don't think that's what she said.
According to the TV news reporter, "Romero found herself agreeing with the district attorney's math, but not in how he was applying it. She says the judge stepped in to clarify the matter, but it was the exchange between her and the prosecutor that was pulled out of the transcript and became the basis for Brown's appeal."
By MR. SMITH (continuing):
Q: Now, I understand that — and what I'm trying to do is make this into a percentage where I can understand it. And so I recognize that as far as your testing, you would prefer to have it as a one in 3 million, but just as another way of looking at it, would it be inaccurate to state it that way?
A: It's not inaccurate, no.
Q: All right. Then in response to my question, would the likelihood that the semen from the DNA found in the panties and the blood from Troy Brown, that it's not the same, would it be -- the chances that they are not a match would be .000033?
A: Yes. That's the way the math comes out.
Q: All right.
THE COURT: Let's make sure. It's the same thing -- it's the same math just expressed differently. Is that correct?
THE WITNESS: Yes. Exactly, your Honor.
Is this how the judge clarified the matter -- by having the witness unequivocally confirm that a DNA type that occurs with a frequency of one in three million in the general population is mathematically the same as a probability of innocence of .00003?

McDaniel v. Brown: Prosecutorial and Expert Misstatements of Probabilities Do Not Justify Postconviction Relief — At Least Not Here and Not Now

Originally posted to Double Helix Law, Jan. 18, 2010 ( as explained here.

In The Double Helix and the Law of Evidence (pp. 173-176), I briefly described the Ninth Circuit Court of Appeals’ muddled opinion upholding a writ of habeas corpus in Brown v. Farwell, 525 F. 3d 787 (9th Cir. 2008). Much has happened since then. First, the Supreme Court granted a writ of certiorari to review whether the Ninth Circuit used the correct legal standard and whether it should have considered a letter written by a geneticist at the behest of defense counsel eleven years after Brown’s trial. Second, the Court received a slew of briefs, including one on defendant’s behalf from “20 Scholars of Forensic Evidence.” Third, after scheduling oral argument, the Court decided that it could dispose of the case on the briefs alone. Finally, on January 11, 2010, the Court issued its unanimous per curiam opinion (sub nom. McDaniel v. Brown).

The case arose from the brutal rape in 1994 of a nine-year-old girl in Nevada. A jury convicted Troy Brown on evidence that included a DNA profile (at VNTR loci) that had an estimated population frequency of 1 in 3 million. On redirect examination, however, the prosecutor induced its DNA analyst, Renee Romero, to accept his mischaracterization of this number as the probability that someone unrelated to the defendant was the source of the rapist’s profile. In addition, Ms. Romero testified that the probability of a VNTR match to “the very next child” of the same parents would only be 1/6500 when the actual probability is less than 1/1024. (She did not mention other tests she had done that would have brought the probability closer to her figure. See False, But Highly Persuasive: How Wrong Were the Probability Estimates in McDaniel v. Brown?, 108 Mich. L. Rev. First Impressions 1 (2009).) Defense counsel neither objected to nor corrected her testimony even though the legal and scientific literature at the time made it indisputable that the prosecution was misconstruing the 1/3,000,000 figure and that the 1/6500 figure was miscomputed.

After losing various appeals and state postconviction petitions, Brown argued for the first time in federal court that the probabilities were incorrectly computed or interpreted and that without the DNA evidence, no reasonable juror could have found him guilty beyond a reasonable doubt. He also argued that trial counsel’s representation of him was so poor as to amount to ineffective assistance of counsel. The district court agreed with both claims. The Ninth Circuit affirmed on the ground that without the “false and highly misleading” DNA evidence, there was insufficient evidence for the conviction and hence a violation of due process under Jackson v. Virginia, 443 U. S. 307 (1979). It did not reach the question of effective assistance of counsel.

The Supreme Court reasoned that the Jackson claim fails because Jackson merely holds that when the evidence against the defendant — whether or not properly admitted according the rules of evidence or the constitution — is insufficient, then, as a matter of due process of law, the conviction cannot stand. In Brown, however, there was “no suggestion that the evidence adduced at trial was insufficient to convict unless some of it was excluded … thus dispos[ing] of [the] Jackson claim.”

As explained in The Double Helix, the more applicable due process claim is that the misstatements about probabilities rendered the conviction fundamentally unfair. The Court barely discussed this “DNA due process” claim, as Brown denominated it. Instead, it insisted that “[r]espondent has forfeited this claim, which he makes for the very first time in his brief on the merits in this Court.”

Although the Court thus avoided the colorable due process issue posed by the admission of the DNA evidence, it is hard to see how Brown could have prevailed even on that belated claim. Admitting the mischaracterized random-match probability may well have been plain error, but it did not rise to the level of a due process violation. See False, But Highly Persuasive, supra. The error regarding the probability of a random match to a sibling is sufficiently technical as not to amount to plain error, let alone constitutional error. Moreover, the prosecution could have produced a correctly computed sibling-match probability close to 1/6500. See id. Therefore, the trial court’s failure to exclude the statistics — to which defendant did not object — hardly seems like the type of error that rendered his trial fundamentally unfair.

In any event, having determined that Jackson was of no assistance to Brown and that Brown had “forfeited” the better due process claim, the Supreme Court remanded the case to the Ninth Circuit to consider whether Brown’s trial counsel had performed so dismally as to deprive him of due process of law. McDaniel v. Brown is thus a narrow, procedural holding regarding the scope of federal habeas corpus claims of insufficient evidence.

Even as to the procedural issue, however, the per curiam opinion raised the hackles of two Justices. The Scholar’s Brief importuned the Court to seize the opportunity to condemn misinterpretations of DNA evidence at trial. It argued that the DNA analyst’s testimony was badly flawed and assured that the Court that the defense expert was entirely correct. (The author of the brief, Bill Thompson, is a University of California-Irvine colleague of the letter’s author, Larry Mueller; the two have been called part of the “combine from Irvine.”) Apparently, the brief did not persuade the Justices that Mueller’s computation of the sibling-match probability was correct. In the Court’s jaundiced eyes, the letter’s “claim that [the state's expert] used faulty assumptions and underestimated the probability of a DNA match between brothers indicates that two experts do not agree with one another, not that [the state's] estimates were unreliable.” Yet, as the one scientific authority cited in the Court’s opinion — a 1996 Report of the National Academy of Sciences report — indicates, Romero plainly transposed the random-match probability and she miscomputed the sibling-match probability — even on her own assumptions! See False, But Highly Persuasive, supra. On these matters, the Scholar’s Brief was correct. Rather than acknowledge this fact, however, the Court only treated Mueller’s two criticisms as hypothetically true. Accepting them solely for the sake of argument, the Court observed that they did not justify exclusion of the DNA evidence in its entirety.

Given the Court’s interpretation of the Jackson claim, however, this discussion of the probabilities is superfluous. If Jackson only means that when the totality of the evidence — admissible or otherwise — is sufficient for conviction, why talk about whether the admissible evidence alone is sufficient? Was the Court giving some credence to the possibility that a modified Jackson claim would be tenable? That is, could due process require a federal habeas court to excise unfounded exaggerations and then to determine whether the reduced corpus of evidence could permit a reasonable juror to convict?

In a concurring opinion, Justices Thomas and Scalia took the Court to task for considering the implications of the Mueller letter on the admissibility of the DNA evidence. Unequivocally rejecting any possibility of a modified Jackson standard like the one that the Ninth Circuit entertained and then misapplied, these Justices
disagree[d] with the Court’s decision to complicate its analysis with an extensive discussion of the Mueller Report. … [T]he report’s attacks on the State’s DNA testimony were not part of the trial evidence and have no place in the Jackson inquiry. … [E]ven if the report had completely undermined the DNA evidence … the panel still would have erred in considering the report to resolve respondent’s Jackson claim. The reason, as the Court reaffirms, is that Jackson claims must be decided solely on the evidence adduced at trial.
The concurring Justices are correct in describing the per curiam opinion’s analysis of the Mueller letter as dicta. But the reason is not that the letter itself was “not part of the trial evidence.” It is that Brown raised the pseudo-Jackson claim rather than the straightforward due process claim about unfair exaggeration in the presentation of DNA evidence. Even if defense counsel had never presented Mueller’s letter to the trial court, he could have relied solely on sources subject to judicial notice to argue on appeal, in state postconviction proceedings, and then again in the federal habeas court proceedings that the trial judge’s failure to correct the prosecution’s mistakes sua sponte deprived him of due process. But Brown did not make this “DNA due process claim” in state court, and the prosecution’s indisputable errors are not relevant to the claim that he did make.