McDaniel v. Brown

2010-01-11

Headline: Limits on using post-trial expert reports upheld as Court reverses a ruling that overturned a rape conviction — federal habeas courts must decide sufficiency using only trial evidence.

Holding: The Court reversed the Ninth Circuit and held that federal habeas courts must assess whether a conviction is supported only by the evidence admitted at trial, and may not rely on a post-trial expert report to overturn it.

Real World Impact:

Prevents federal habeas courts from overturning convictions using post-trial expert reports.
Confirms DNA trial evidence remains strong despite imperfect statistical descriptions.
Sends case back for further review of ineffective-assistance claims.

Topics: DNA evidence, habeas review, sexual assault conviction, expert testimony reliability

Summary

Background

A Nevada man convicted of raping a nine-year-old child challenged his conviction in federal court after a later expert report questioned parts of the DNA testimony given at trial. At trial the State’s DNA expert said the crime-scene DNA matched the man and gave a random-match figure (one in 3,000,000), while a later family-funded test showed a different figure (one in 10,000). Years after the trial, a new expert (the Mueller Report) said the trial testimony had statistical errors and understated how likely a brother might match the DNA.

Reasoning

The core question was whether a federal court reviewing the sufficiency of evidence on habeas could rely on that post-trial expert report. The Court said no: when asking whether a jury acted rationally, a federal habeas court must consider only the evidence admitted at trial and view it in the light most favorable to the prosecution. The Court found the trial record contained strong DNA and other evidence linking the man to the crime and held the Ninth Circuit erred in excluding trial evidence or treating the later report as if it could defeat the jury verdict.

Real world impact

The ruling clarifies that later expert studies cannot be used to reweigh trial evidence under the Jackson standard and that DNA testimony remains powerful even when some statistical descriptions were imperfect. The Court reversed the Ninth Circuit and sent the case back for further consideration of related claims, like ineffective assistance of counsel.

Dissents or concurrances

A concurring opinion emphasized the same point and said the opinion need not analyze the post-trial report at length because such reports do not belong in a Jackson review.