Academic journal article Michigan Law Review

Cabining Judicial Discretion over Forensic Evidence with a New Special Relevance Rule

Academic journal article Michigan Law Review

Cabining Judicial Discretion over Forensic Evidence with a New Special Relevance Rule

Article excerpt


On January 20, 1980, Santae A. Tribble was convicted of armed robbery and the felony murder of a taxi driver he had never met.1 He spent the next twenty-eight years in prison, where he contracted HIV and hepatitis.2 Mr. Tribble's conviction was based on testimony3 from the FBI Crime Laboratory that there was a high degree of similarity between his hair and hair found at the scene.4 But, in 2012, mitochondrial DNA testing revealed that Mr. Tribble could not have contributed any of the hairs found at the scene.5 One of the hairs the FBI had matched to Mr. Tribble had come, in fact, from a dog.6 In February 2016, a judge ordered the District of Columbia to pay Mr. Tribble over $13 million in damages.7

In 2015, the Justice Department and the FBI admitted that 26 of the 28 examiners in the FBI Crime Laboratory had given exaggerated testimony from 1972 to 1999;8 these examiners had overstated to juries the actual probative value of hair-match analysis.9 Of the 268 trials with overstated hair-match evidence examined by the National Association of Criminal Defense Lawyers and the Innocence Project, 14 of the defendants "sentenced to death ... [had] been executed or died in prison."10 During those trials, there would have been no reason for the judges, prosecution counsel, or defense counsel to suspect they were being presented with exaggerated testimony. And the problem is broader than hair analysis: since 1989, 524 exonerations nationwide involved false or misleading forensic evidence.11

Forensic science is defined as "the application of scientific principles and techniques to matters of criminal justice especially as relating to the collection, examination, and analysis of physical evidence."12 The public's relationship with forensic science is complicated, and forensic evidence has become paramount in criminal trials. Many jurors have come to expect forensic evidence in criminal trials,13 even though most trials involve none.14 Some research suggests that this so-called "CSI Effect" makes jurors less willing to convict in the absence of forensic evidence.15 As a result, investigators will sometimes perform unnecessary tests in the field simply to have something "scientific" to present to a jury.16 These tendencies underscore the importance of ensuring only accurate and reliable forensic evidence reaches a jury: as the Supreme Court noted in Daubert v. Merrell Dow Pharmaceuticals, Inc., "[e]xpert evidence can be both powerful and quite misleading because of the difficulty in evaluating it."17

Part I of this Note describes the current federal evidentiary framework for admitting expert scientific testimony. Part II discusses the problems with forensic science in criminal trials: the lack of foundational scientific validity, the lack of any rigorous system of laboratory accreditation or certification system for individual practitioners, the institutional barriers to improving the system, and the problematic ways in which judges and juries interact with forensic evidence. Part III proposes a new special relevance rule excluding non-DNA forensic evidence in criminal trials under certain circumstances absent a significant showing of scientific validity. This new rule would protect the integrity of the legal process in the face of inaccurate evidence. Finally, Part IV addresses potential counterarguments to the adoption of this new special relevance rule.

I. Forensic Evidence in Federal Courts

The admissibility of forensic evidence, presented through expert testimony, is governed by two rules in federal court: Federal Rules of Evidence 702 and 403.18 These rules often have analogues in state evidence codes19 and are motivated in part by concerns about the high degree of deference juries often give to expert testimony.20 To prevent juries from over-valuing expert opinions, care must be taken to ensure the testimony juries hear is based on reliable and valid methodologies.

Rule 702 governs when expert testimony may be admitted:

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

(a) the expert's scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

(b) the testimony is based on sufficient facts or data;

(c) the testimony is the product of reliable principles and methods; and

(d) the expert has reliably applied the principles and methods to the facts of the case. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed


An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.