Fingerprints and Admissibility: Friction Ridges and Science

Article excerpt

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. …