FORENSIC SCIENCE: Limitations and Misconduct

False testimony, exaggerated statistics, and laboratory fraud have all led to wrongful convictions. Jurors often give forensic science more weight, because it is provided by “experts.” However, when misconduct occurs the added weight is damaging and can lead to wrongful convictions. In some cases, labs and their personnel are not impartial, because they are too closely tied to police and prosecutors. Other times, a criminologist who lacks necessary knowledge may exaggerate findings and does not have to worry about being caught because the lawyer, judge, and jury have no background in the relevant science. In many cases, critical evidence is destroyed making re-testing to uncover the misconduct is impossible.

The Facts

Many people deal with forensic evidence at different stages in the criminal process. Identification, collection, testing, storage, handling, and reporting of evidence can be deliberately or accidentally mishandled at any stage:

  • At the crime scene, evidence can be planted, destroyed, or mishandled.
  • At the forensic lab, evidence can be contaminated, poorly tested, consumed or mislabeled.
  • In the report, results can be misrepresented DNA exonerations have revealed a number of cases where results were reported on evidence when no test was actually done!

Examples of Forensic Misconduct that have lead to wrongful convictions:

  • Fred Zain, the former director of the West Virginia state crime lab, testified for the prosecution in 12 states over his career (many in West Virginia and Texas) and has left a trail of fabricated results, false testimony on results, and has willfully omitted evidence from his reports.
  • Pamela Fish, a Chicago lab technician, has testified for the prosecution about false matches and suspicious results in at least eight cases that secured convictions, but were later proven innocent by DNA testing.

Current Issues in Forensic Science – Hair Microscopy

In 2012, the FBI commenced an internal review of microscopic hair analysis cases, following a trio of DNA exonerations in Washington DC (from 2009-2012) where all three defendants were convicted on FBI microscopic hair comparison evidence which later turned out to be wrong.  At that time, the FBI estimated that approximately 21,000 cases involved microscopic hair analysis would be reexamined.  In July of 2012, an historic agreement was reached between the FBI, the Department of Justice, the Innocence Project and the National Association of Criminal Defense Attorneys (NACDL).  This review purposely included the Innocence Project and the NACDL to:  underscore the non-adversarial nature of the review process; and to facilitate the identification of those who were affected by the flawed evidence and the procurement of transcripts essential to the review process.* 

IPMN is working to identify key partnerships in Minnesota to conduct a full review of the cases in Minnesota where evidence of microscopic hair analysis was conducted.  IPMN would then identify any of these hair microscopy cases where actual innocence is alleged and a case review is possible.

The Remedies

A number of reforms could limit the number of cases where forensic misconduct occurs. For example, the Innocence Project suggests states impose standards on the preservation and handling of evidence. In addition, when exonerations suggest misconduct of an analyst or that a facility lacked proper procedures or oversight, independent audits of their work in other cases should take place to uncover the possibility of other wrongful convictions.

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 *Source:  NACDL – “Microscopic Hair Comparison Review Project,” –