Fingerprints and Admissibility: Friction Ridges and Science

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ABSTRACT

For over a century, friction ridges, most notably fingerprints, have been considered the most positive method of personal identification. Friction ridge identification was based on the premise that nature did not repeat and the comparison technique appeared to have objective standards for reaching a conclusion. The recording of fingerprints was simple, non-intrusive, and required only minimal supplies. Recent court challenges have brought into question the validity and reliability of fingerprinting as a science. The Supreme Court determined that the Federal Rules of Evidence require scientific evidence to be scientifically valid before it enters the courtroom. The long-held premises of fingerprinting as an application had not previously undergone a serious challenge. Scientists, police, and lawyers struggle to design the juridical intersection where law and science cross paths. Challenges to fingerprints were seen to cross these boundaries: They were unwanted and generally resented. Over the years fingerprinting has progressed and is now capable of meeting the standards set by modern courts. The current challenge is for the friction ridge practitioner community to transition from the historical police mind-set to a scientific mind-set. This requires a cultural change, albeit a professional one, that many practitioners and agencies may be ill-equipped to handle.

"I sometimes think that the most injustice which is done in the execution of our criminal law, is done innocently by those who are honestly mistaken in identification, or are overanxious to assist in the prosecution of the law to the extent that they do not realize either their own recklessness, or the responsibility for the statements they are marking." (The Hon. William E. Leahy, Washington D.C., February 1922--as reported in Personal Identification, Wentworth and Wilder, 1932, p7).

For over one hundred years, friction ridges (most notably fingerprints) have been considered the most positive method of personal identification. During the late 1880's fingerprint identification was first employed in India when an employee of the East India Company decided to use fingerprinting to prevent impersonation by locals using fingerprints to sign documents. The idea traveled to England a few years later and made its North American debut at the 1904 St. Louis World's Fair when a detective from Scotland Yard gave a presentation on the subject. The idea was brought back to Canada by Edward Foster of the Dominion Police who had been in St. Louis guarding a display of gold (Ashbaugh, 1999).

Friction ridge identification was based on the premise that nature did not repeat exactly. The comparison technique appeared to have objective standards for reaching a conclusion based on a quantity of details but was mostly intuitive pattern recognition. These details, called Galton details after Sir Francis Galton an early supporter of fingerprint identification (Galton, 1892), appear at the ends of friction ridges or where friction ridges join together. Galton details are also called friction ridge characteristics or points.

The recording of fingerprints was simple, non-intrusive, and required only minimal supplies: printer's ink and paper. This procedure appealed to practically-minded police managers but as fingerprints became more deeply embedded in the realm of law enforcement, and as their confidence with the technique grew, main stream scientists seemed to lose interest in the discipline. A few researchers interested in fingerprints worked in related sciences, such as embryology, (Wentworth & Wilder 1932), dermatoglyphics, and anatomy but fingerprinting was generally left in the hands of the police, military and other government agencies. Fingerprint identification was considered absolute--what other questions were there? Police agencies assurance in fingerprints as the acme of uniqueness effectively stunted further scientific inquiry and research.

Recent court challenges, however, have brought into question the validity and reliability of the method as a science (US v. Mitchell, 1999; US v. Mitchell, 2004; US v. Plaza, 2002). The long-held premises of fingerprinting as an application had not previously undergone a serious challenge (Moenssens, 2003). During the early years of fingerprinting there was minor controversy (see e.g., Wilton, 1938), but it was based on issues such as who first published the idea of using ridges for personal identification, or was first to think of using friction ridges to connect a person to a crime scene--essentially bragging points for individuals or agencies (Faulds, 1880; Herschel, 1880). The central issue, uniqueness, was rarely, if ever, questioned. Other issues predominated. For example, developing a storage and retrieval system for fingerprints was central to its utility in police work. Any challenges occurred within the confines of government committee discussions or official meetings as opposed to open court or in the scientific literature.

At the outset, fingerprinting was in direct competition with an anthropometric identification system developed by Alphonse Bertillon and based on eleven body measurements (Wentworth, 1932). The anthropometric system, however, was time consuming and the measurements were not taken consistently. Debate centered on which methods were the easiest to use and most accurate (Gillam, 2001). Fingerprint identification eventually prevailed due to its simplicity, superior accuracy, and systematized precision. During the middle of the last century, the fingerprint community reviewed their position on standards for conclusions (Identification News, 1973). At the time, Canada had an identification standard of around ten Galton points. Although other countries had similar standards, the quantity of points used for identification fluctuated based on the clarity of the print and at the whim of the examiner without standardized or objective criteria for doing so. The International Association for Identification tasked a committee to investigate this situation and, after a three year study, an agreement was reached. The critical portion of the report read as follows:

"The International Association for Identification, assembled in its 58th Annual Conference at Jackson, Wyoming, this First Day of August, 1973, based upon a three-year study by its Standardization Committee, hereby states that no valid basis exists at this time for requiring that a pre-determined minimum number of friction ridge characteristics must be present in two impressions in order to establish positive identification. The foregoing reference to friction ridge characteristics applies equally to fingerprints, palm prints, toe prints and sole prints of the human body" (Identification News, 1973).

Although this statement changed the essence of the identification methodology from a quantity threshold to an evaluation of available data (Ashbaugh, 1985), few examiners recognized the difference--most functioned as before, consciously or unconsciously seeking a quantity of data to satisfy a personal or internal standard for identification (Evett & Williams, 1996). Training curricula changed and attempted to teach the new approach but did not specifically address the evaluative nature of the process (Ontario Police Manual, 1987).

It may be argued that, with this change, novice trainees were at a disadvantage, unlike senior examiners, they did not have experience using any standard--even an incorrect one. As such, most novice examiners simply adopted the old quantity system but a few tried to make the new evaluative system work. As a result, they began to question the status quo and to put forward new ideas to address the lack of evaluative protocol. Experienced examiners considered this conduct disruptive and viewed it as a challenge to the validity of the method by inexperienced (but university educated) upstarts.

Given the above, scientists, police, and lawyers struggled to design the juridical intersection where law and science cross paths. In the United States, the Supreme Court determined that the Federal Rules of Evidence require scientific evidence to be scientifically valid before it enters the courtroom. The Supreme Court trilogy of decisions on this topic (Daubert v. Merrill Dow Pharmaceuticals, 1993; General Electric Co. v. Joiner, 1997; Kumho Tire Co. Ltd. V. Carmichael, 1999) offered guidance and refinement of what constitutes an expert, what is science, and the legal meaning of validity. The tension between the "old" and "new" approach was largely a result of the push-and-pull between the needs of the policing professional culture and the science professional culture.

Freidson (1986) argued that professional groups work within constantly negotiated boundaries of formal knowledge. Using the Federal Courts to analyze such negotiations, he noted expert witnesses make judgments and evaluations that fact witnesses are not allowed to make, at least in court. As such, Freidson argued that experts allow judges to arbitrate the reliability of scientific evidence, in essence crossing the boundary into their "knowledge jurisdiction," in exchange for their (the expert's) expansion into the legal proceedings. In doing so, the experts relinquish part of their "knowledge jurisdiction" to the judges to enter into a foreign domain, the "legal jurisdiction." These exchanges, Freidson maintains, are acknowledgments and negotiations of the boundaries of professional groups through which society recognizes as nominal domains of specialized expertise; to wit, "science" and "the law." Done properly, these negotiations produce a detente, a mixture of formal and informal brokering to produce a workable treaty between otherwise conflicting cultures.

One may argue, however, that there is a potential …