The President’s Council of Advisors on Science and Technology has concluded that forensic bite-mark evidence is not scientifically valid and is unlikely ever to be validated, according to a draft report obtained by The Intercept. The report, titled “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods,” is marked as a “predecisional” draft created August 26 that is not to be quoted or distributed, though the title page suggests the report will be made public this month. The report reviews a handful of common forensic practices, so called feature-comparison disciplines, or pattern-matching practices — bite-mark analysis, fingerprint and firearm analysis, shoe tread analysis, and DNA mixture analysis — each of which involves an “expert” looking at a piece of evidence and eyeballing whether it matches a particular image, person, or object. The report discusses whether each practice has been scientifically validated, what it would take to do so, and how each practice should be used in court, if at all.
The council said fingerprint matching had produced high error rates, and criticized some firearm analysis. The National District Attorneys Association (NDAA) is critical of the draft report. It says that “the forensic disciplines that the [council] authors attack are (and have been) reliably used every day by investigators, prosecutors, and defense attorneys across the United States to aid in both exonerating the innocent and convicting the guilty,” calling the council conclusion
“scientifically irresponsible.” The prosecutors said that, “Adopting any of their recommendations would have a devastating effect on the ability of law enforcement, prosecutors and the defense bar to fully investigate their cases, exclude innocent suspects, implicate the guilty and achieve true justice at trial.” The statement was issued by NDAA president Mike Ramos, the elected district attorney in San Bernardino County, Ca.