Is “Bite Mark Analysis” a Reliable Forensic Science? Washington Post Raises Questions.

Filed under: Criminal Law by Contributor @ March 18, 2015

In a damning expose, the Washington Post has laid bare the junk science that is “bite mark analysis,” the forensic method of looking at indentations found in human skin thought to be caused by human teeth.  The patterns are then matched to plaster molds taken of the teeth of suspects.  The article not only calls into question the scientific validity of bite mark analysis, but also questions the ethics of those experts who practice in the field.  The story is worth reading in full, but here are the highlights:

  • According to the Innocence Project, which we have collaborated with in previous cases, 24 people have been exonerated after they were either convicted or arrested because of the assertions of a bite mark analyst.  The Innocence Project estimates that there are still hundreds of innocent people in prison today due to flawed bite mark testimony, including 15 awaiting execution.
  • In 2009, the National Academy of Sciences published a highly critical congressionally commissioned report on the state of forensic science in the courtroom.  While addressing a number of different forensic methods, the report was particularly critical of “pattern matching,” specifically bite mark matching.  The report states that there is “no evidence of an existing scientific basis for identifying an individual to the exclusion of others.”  Of course, to find “beyond a reasonable doubt,” the exclusion of all others is the exact standard our criminal justice system requires in order to convict.
  • In the wake of the The National Academy of Sciences report,  a Blue Ribbon Panel was established by the White House to look into questionable forensic science in the courtroom.  Large professional organizations promised to establish best practices, take ethics more seriously, and do a better job of policing their members.  Still, since 2009, individuals continue to be convicted and sent to prison largely on the singular testimony of so-called “bite mark experts.”
  •  According to the Washington Post, bite mark analysts wield significant power in the American Academy of Forensic Sciences, the largest and most influential American forensic organization, which in turn provides credibility for those claiming expertise in forensic dentistry.  Despite the National Academy of Sciences report, the AAFS continues to push bite mark analysis as a valid forensic science .
  • Dr. Michael Bowers, a dentist, college professor, and deputy medical examiner in Ventury County California, has done extensive research on the practice of bite mark analysis, and has for decades been trying to eliminate the method, which he calls both “false and misleading” and a “corruption of justice”, from the courtroom.  In response to Dr. Bowers’ research, the President of the American Board of Forensic Odontology filed an ethics complaint against him with the AAFS, threatening his credibility and membership in the larger body — effectively removing a critic from the courtroom.
  • Researchers at the University of Buffalo are in the process of publishing a series of studies demonstrating that the notion that skin is capable of registering bite marks in a way that makes them identifiable is without basis in science.  Like Dr. Bowers, the research team has been subject to vicious, personal attacks.

The United States Justice Department announced late last year that it is establishing another committee to study the scientific validity of bite mark analysis.  Perhaps unsurprisingly, a majority of the members appear to have their minds made up– the chairman is a practicing bite mark analyst.

“Bite mark analysis” (and other similar, flawed forensic sciences) will continue to be in the news as innocent individuals convicted of crimes they did not commit are set free, as researchers continue to question the science involved in criminal forensics, and as the so-called experts continue to entrench their practice despite all evidence to the contrary.  The question we have to ask is how many more innocent people will we let be convicted before we demand that these flawed sciences undergo rigorous testing to either achieve full validation, or be banned entirely from our nation’s courtrooms?  

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