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 (http://www.personal.psu.edu/dhk3/blogs/DoubleHelixLaw/2010/01/mcdaniel-v-brown-prosecutorial-and-expert-misstatements-of-probabilities-do-not-justify-postconvicti.html) 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.