In his article entitled Fingerprint Admissibility Rulings, Simon Cole (2004) posed some intriguing questions about the admissibility of fingerprints as evidence in a court of law:

Are judges truly prepared to demand evidence of reliability for everything? Or are there some long-held beliefs that we just know are true? Might there be some beliefs that have been held so long because they are true, even though they cannot be proven? (p. 1103)

In a landmark decision by the U. S. Supreme Court in 1993, Daubert v. Merrell Dow Pharmaceuticals, the court ruled that “federal judges were directed to examine the scientific method underlying expert evidence and admit that which is scientifically reliable and relevant” (Melnick, 2005, p. 30).

Historically, when offering an identification based on a latent print found at a crime scene compared with a known print from a suspect, fingerprint examiners testify in court with “absolute certainty” (Cole, 2004, p. 1196) that “the suspect’s finger is the only finger in the world, living or dead, human or primate, which could have produced the latent impression” (Cole, 2004, p. 1196). Cole (2004) observed that “fingerprint examiners still believe it is appropriate to testify that they are absolutely certain that they do not make errors, even though clear evidence demonstrates that the technique does make errors” (p. 1197).

Cole (2004) questions why courts have allowed forensic expert witnesses to testify that a fingerprint is unique. He concludes that “while uniqueness is impossible to prove, it is easy to believe” (p. 1198). Acceptable scientific thought may accept that “a repeated inability to find duplicate fingerprint patterns would allow one to induce that duplicates do not exist” (p. 1198), but demands that “one must always remain open to the possibility that the next fingerprint observed may be a duplicate” (p. 1198). Despite this inconsistency, the record suggests most courts accept that “all fingerprints are unique” (p. 1199).

People v. Jennings, in 1911, is the first recorded decision in the United States to admit forensic fingerprint evidence (Acree, 1999, p. 455). Cole (2004) observed that “the Jennings court’s inquiry into forensic fingerprint identification consisted of little more than noting that other legal and scientific authorities viewed it as accurate” (p. 1218).

Having been found guilty, based in part on fingerprint evidence, Jennings appealed his case. The Illinois Supreme Court upheld the conviction based upon acceptance that “standard authorities on scientific subjects discuss the use of fingerprints as a system of identification, concluding that experience has shown it to be reliable” (Acree, 1999, p. 455).

The first post-Duabert court case to challenge forensic fingerprint evidence was United States v. Mitchell. The defense attempted to call an expert witness “to testify to the limitations of fingerprint evidence” (Cole, 2004, p. 1225). Since the case was decided in a bench ruling instead of a written decision, “the length and thoroughness of the Mitchell record have yet to be surpassed by any other Daubert challenge” (Cole, 2004, p. 1225).

Cole (2004) observed that the Court allowed fingerprint evidence based on a study known as “the 50K X 50K study” (p. 1226). It compared 50,000 fingerprints and concluded that “the probability of two identical complete fingerprints existing as being 1 in 1097” (p. 1227).

The first written decision to evaluate the Daubert ruling was the United States v. Havvard. During his trial, Havvard moved to exclude forensic fingerprint evidence, but the court denied his motion. The court concluded that latent print identification was acceptable based on expert testimony, therefore met the Daubert standards (Cole, 2004, p. 1233).

The court ruled that latent print identification methods had been tested adequately for more than 100 years. Cole (2004) shows how the court “concluded that the methods had been subjected to sufficient peer review” and “the defense has presented no evidence of error rates, or even of any errors” (p. 1233). Cole (2004) concludes that “the Havvard court shifted the burden of proof by faulting the defense for not presenting evidence of the error rate when Daubert requires the part proffering the technique to provide evidence concerning its error rate” (p. 1237).

The first ruling in the United States to restrict the admissibility of fingerprint evidence would later be overturned by the same judge who made the ruling. In Llera Plaza I, the Eastern District Court of Pennsylvania ruled that “fingerprint examiners could describe similarities and differences between the latent print and the known print, but could not testify to their opinion about whether the two prints derived from a common source” (Cole, 2004, p. 1242).

The court overturned itself in Llera Plaza II, citing a reconsideration of expert testimony. Cole (2004) recorded the essence of the decision: “On further reflection, . . . I disagree with myself” (p. 1255). The court specifically used the argument that this kind of evidence is “sufficiently reliable in England” (Cole, 2004, p. 1256).

Cole (2004) concludes that even though fingerprint evidence routinely fails under the rigorous validation of scientific scrutiny, it is most likely that fingerprints will continue to be accepted by courts as absolute proof of identity. He concedes that courts will not “demand that forensic fingerprint identification prove its case,” because “to do so would be to admit that the courts admitted evidence without subjecting it to scrutiny for nearly a century and were complicit in the admissibility of evidence that lacked validation” (p. 1275).

Acree, M. A. (1999, Jul/Aug). People v. Jennings: A significant case for fingerprint science in America. Criminal Justice Periodicals, 49(4), 455.

Cole, S. A. (2004, Summer). Grandfathering evidence: Fingerprint admissibility rulings from Jennings to Llera Plaza and back again. The American Criminal Law Review, 41(3), 1189-1276.

Melnick, R. L. (2005, July). A Daubert motion: A legal strategy to exclude essential scientific evidence in toxic tort litigation. American Journal of Public Health, 95(S1), 30-34.