Written by Aischa S. Prudhomme, CLPE – May 2012
Abstract
Fingerprint identification has risen from its once humble beginnings to become one of the most definitive and reliable disciplines within the criminal justice system. Although it has most recently become popularized by modern primetime television shows like “CSI”, fingerprint identification has been considered the gold standard in the field of forensic science for over a hundred years. But what about the science of fingerprint identification and how has it evolved through modern times; and most importantly, can it overcome the judicial challenges of the past two decades? Have these challenges truly hindered the forensic community, or have they instead merely assisted in strengthening the science?
The first part of this paper sets the foundation by examining the origins of fingerprint identification, including a timeline account of its many applications throughout history, as well as an introduction to the many pioneers whose scientific research has facilitated in setting the foundation for its application in forensic science. It also discusses the biological processes involved in the growth of friction ridge skin during the critical stages of fetal development; focusing on the premises of permanence and uniqueness, the fundamental scientific bases of fingerprint identification. It then presents a comprehensive overview of the methodology involved in fingerprint identification and provides a comparative analysis of the traditional versus modern techniques utilized today. Additionally, it discusses the demanding role of the fingerprint examiner today and the challenges which now face forensic scientists in the modern day judicial system.
The second part of the paper discusses Daubert v. Merrell Dow Pharmaceuticals, Inc., the Supreme Court case that set a new precedent for the admissibility of scientific evidence and/or expert testimony; and its impact on forensic science, specifically within the discipline of latent print examination. The Court’s ruling outlines a prescribed standard, which is comprised of four prongs: (1) empirical testing of the theory/technique and peer review and publication of the theory/technique, (2) the known or potential error rate, (3) standards controlling the technique’s operation, and (4) general acceptance within the scientific community. Each of the four prongs, known collectively as the “Daubert standard”, are deconstructed and analyzed, then correlated to the correspondent data utilized from a compiled literature review of the relevant fingerprint science, with the intent to: (A) demonstrate the method’s definitive admissibility under the Daubert requirements and to (B) substantiate its status as a valid scientific method applicable to distinguishing individual human identity and in identifying the source of latent print impressions through the use of fingerprints.
Introduction
What is the science of fingerprint identification? It seems like a simple enough question, but to understand the science one has to first look at its history. Fingerprints can be traced as far back as prehistoric and ancient times when it was first used in primitive carvings and drawings as a form of artistic expression; and later during early Chinese civilization, BCE, when it was used primarily as a civil application for the endorsement of contract deeds, document seals and land titles.
It was only later, during the late 1700’s, that the uniqueness of fingerprints became the focus of scientific study; and by the late 1800’s, fingerprint identification had become the preferred method for human identification, particularly within the criminal justice system. Subsequently, it was from its criminal application that fingerprint identification further evolved, becoming an early investigative tool used for solving crimes; and so it remains today in the modern field of forensics, as the science of fingerprint/latent print identification (Ashbaugh, 1999).
History
In 1870, a British surgeon by the name of Dr. Henry Faulds became one of the first scientists to propose the use of fingerprints as a means of personal identification, as well as its value in solving crimes. His findings were documented in letters and writings that were then published in the scientific journal Nature. Later his work would be passed on to British anthropologist Sir Francis Galton, a cousin to Charles Darwin, whose interest in genetics lead him into the field of anthropometry; and later, to research involving the significance of the distinct variations in minutiae that are found in fingerprints (Ashbaugh, 1999).
Through his anthropometrical research and studies focusing on friction ridge detail in the skin of the hands and feet, Galton was the first to scientifically prove that fingerprints were both permanent and unique; and in 1892, his findings were published in the book Finger Prints. In his book, Galton discusses the role of permanence and uniqueness and its correlation to the presence of the distinct minutiae which are vital to the identification process. When referring to the papillary ridges, Galton states:
We shall see that they form patterns, considerable in size and of a curious variety of shape, whose boundaries can be firmly outlined, and which are little worlds in themselves. They have the unique merit of retaining all their peculiarities unchanged throughout life, and afford in consequence an incomparably surer criterion of identity than any other bodily feature. (1892, p. 2).
His name has coined the term that is still in use today when referring to the minutiae or Galton “points” of identification.
Once it had been established as a means of identification, fingerprints became an integral part of the criminal justice system. Not only was it utilized in the recording, classification and identification of criminal arrest records but it was also used in solving criminal cases where latent prints were recovered. Seeing the potential crime solving benefits of latent fingerprint identifications, it was around this time that scientists began experimenting with techniques using chemicals and powders for the purpose of developing latent fingerprints at crime scenes (Barnes, 2011). Consequently, the first homicide case to be solved using fingerprint evidence occurred in Argentina in 1892 and involved the identification of a bloody thumbprint found at the scene of the crime (Ashbaugh, 1999). Since that time, latent print evidence has become one of the most valuable forms of evidence used in criminal trials today.
In 1891 Juan Vucetich, a statistician and Argentine police official, utilized data from Galton’s research to design what is considered by many to be the first workable system for recording, classifying and identifying the fingerprints of criminals. Incidentally, this system is still in use today in many of the Spanish-speaking countries. However, it was in 1892 that Vucetich’s training became instrumental in identifying a bloody thumbprint taken from the door post of a house in Buenos Aires, which was the scene of a gruesome homicide involving the murder of two boys. The bloody print was matched to the thumb of Francisca Rojas, the woman accused of murdering her two sons. Vucetich’s work in fingerprints has credited him with being the first to utilize fingerprint identification specifically as a function of the criminal justice system (Ashbaugh, 1999).
Another figure who was essential in the adoption of fingerprint classification for its use in criminal applications was Sir Edward Henry. In 1894 in collaboration with Sir Francis Galton, Henry devised a formula using the nine fingerprint pattern classifications originally named by German professor Dr. Johannes E. Purjinke in 1823 based on research from his published thesis titled “Commentary on the Physiological Examination of the Organs of Vision and the Cutaneous System” (Ashbaugh, 1999). Henry’s formula provided a workable method for recording, classifying, categorizing and filing criminal fingerprint records, which allowed for greater efficiency, reliability and ease of use (Barnes, 2011),
Henry’s classification system was developed in India and first employed by the Bengali Police in the Lower Provinces where Henry was appointed Inspector General; and by 1901, the system was officially adopted in England by the Scotland Yard (Barnes, 2011). And in 1904 in the United States, the fingerprints of all inmates housed at Leavenworth Federal Prison were being systematically recorded, which were to become the first Federal fingerprint records commencing the U.S. Government’s official collection (Barnes, 2011).
Today, the FBI’s fingerprint records have grown to over 100 million, including both civilian and criminal records, and are maintained within a computer database program called IAFIS (Integrated Automated Fingerprint Identification System), which is recognized as the largest biometric database in the world (U.S. Dept. of Justice – FBI, 2011) . Although computer database programs, such as IAFIS and AFIS (Automated Fingerprint Identification System), designed for the automation of these records are most commonly used today, many law enforcement agencies continue to utilize Henry classification in conjunction with these newer automated systems (Evidence Technology Magazine, 2008).
Around the time Henry was developing his classification system other discoveries were being made within the biological spectrum of fingerprint pattern development. Based on previous primate research conducted in 1883 by Dr. Arthur Kollman of Germany on the embryological growth of friction ridge skin and its correlation to volar pad development, other primate studies involving friction ridge development were beginning to come underway (Barnes, 2011).
In 1897 a Zoologist named Harris Hawthorne Wilder published his first paper titled “On the Disposition of the Epidermic Folds Upon the Palms and Soles of Primates” and began what would entail 30 years of research into the morphology of friction ridge skin, focusing on palmar and plantar dermatoglyphics and variations in genetics and race. During his research, Wilder proposed that friction ridge patterns in primates were associated with volar pad development and undoubtedly set the foundation for further research into the evolution of friction ridge development (Barnes, 2011).
One scientist who was particularly influenced by Wilder’s research was Inez Whipple, a co-worker who later became Mrs. Inez Whipple Wilder. In 1904 she published what is considered today a landmark study in the fields of genetics and ridgeology. Her paper titled “The Ventral Surface of the Mammalian Chiridium” is a dissertation on the evolutionary processes between reptiles and mammals, which focuses on the development of friction ridge skin as it evolved according to man’s evolutionary needs for survival. She describes the process as an evolutionary occurrence involving the configurations of reptilian volar scales, which over time fused into rows to become epidermal ridges as certain species evolved into mammals; therefore allowing for friction in grasping and climbing, in accordance with man’s development (Barnes, 2011) .
As a result of these advancements in scientific research and the many contributions from both the scientific and law enforcement community, fingerprint identification had become generally accepted as a valid scientific method for human identification. Most importantly, improved techniques for developing and identifying latent prints of evidentiary value were instrumental in further propelling this general acceptance status among the judicial system as well. In fact the first U.S. appellate case involving the admissibility of fingerprint testimony, People v. Jennings (1911), was upheld on the basis that the court recognized fingerprint identification as a science that requires careful study and the expertise of those trained in the practice of its methods; and under those circumstances, expert testimony should be deemed appropriate in supporting the jury’s understanding of fingerprint evidence. People v. Jennings became a landmark case in the United States because it was the first appellate case to challenge the admissibility of expert fingerprint testimony (Barnes, 2011).
Another legal case concerning the use of latent fingerprint evidence, People v. Crispi (1911), was to become the first judicial conviction in the U.S. determined solely from evidence involving the identification a latent fingerprint. During trial, the fingerprint expert’s testimony and presentation of the evidence was so convincing even the defendant tried to change his plea to guilty (Barnes, 2011).
By 1914, the science of fingerprint identification had once again evolved to include the use of poroscopy; a theory first proposed by Dr. Edmond Locard. In “The Legal Evidence by the Fingerprints”, a published article of his research, Locard explains how sweat pores within the impressions of friction ridges can also be used to support fingerprint comparisons by providing supplemental data toward the weight of the conclusion (Ashbaugh, 1999). Further scientific research involving the permanence and uniqueness of third level detail, conducted by Harris Hawthorne Wilder and Bert Wentworth, would also support Locard’s theory (Ashbaugh, 1999).
As the momentum of fingerprint identification increased so did the need to form a governing body to oversee it. In 1915 Harry Caldwell, inspector of the Oakland, California Police Department’s Bureau of Identification, began to form an assembly of those in the profession of fingerprint identification. Twenty-two members convened to form what is known today as the International Association for Identification (IAI). The IAI has created the benchmark for those in the field of forensic identification and is responsible for the establishment of the certification of fingerprint examiners (theiai.org, 2011).
Through its professional journal, the Journal of Forensic Identification (JFI), the IAI has encouraged research toward the progress of forensic identification and has consistently published studies that are peer-reviewed not only by those in the field of forensic science but throughout the entire scientific community as well (theiai.org, 2011). There are other organizations and technical working groups who are also dedicated to identification research and were specifically formed to develop best-practices guidelines within the forensic identification community (SWGFAST, 2011); however, the IAI remains as the foremost authority in the field (James & Nordby, 2005).
SWGFAST (Scientific Working Group on Friction Ridge Analysis Study and Technology) formerly known as TWG (Technical Working Group), was initially formed by the FBI as a short term project to address the need for the development of quality standards and protocols within the latent print discipline. On June 10, 1995, fifteen prominent figures within the latent print community collaborated in discussions that took place for a total of eleven days in order to establish consensus guidelines relative to friction ridge examinations. The mission was so successful the FBI decided to re-establish the group as an ongoing scientific working group, and in 1998 the name SWGFAST was officially adopted. Since that time, SWGFAST has been instrumental in establishing the standard operating procedures, quality practices and protocols which have been adopted by forensic practitioners and generally accepted within the forensic community and judicial arenas alike (SWGFAST, 2011).
Throughout the course of the mid to late 20th century there were many more important scientific breakthroughs and landmark judicial rulings concerning fingerprint identification and its general acceptance as a valid science. Listed below is a brief timeline and summary of these historical contributions.
- July 1924- Establishment of the Identification Division which maintained the federal criminal fingerprint records under the U.S. Justice Department’s Bureau of Investigation (Barnes, 2011).
- April 1939- The Washington County Supreme Court upheld the decision on a habitual offender conviction in State v. Johnson, 1939. The lower court’s verdict was based on a fingerprint identification using certified copies of the defendant’s prior conviction records (Barnes, 2011).
- May 1939- The sinking of the USS Squalus was the first U.S. disaster in which fingerprints were used to identify the victims (Barnes, 2011).
- 1940- An appellate judge in Hamilton Texas upheld a conviction that was based on the identification of a latent fingerprint. In his decision, the judge proclaimed there was sufficient proof in the classification and identification of thousands of fingerprints conducted in the U.S. to hold that fingerprints were unique. He further added that the burden of proof lay with the defense to show two individuals who share the same fingerprints (Barnes, 2011).
- 1940- The FBI Disaster Squad is formed in response to the Pan Am Airliner crash in Lovettsville, Virginia. Members of the FBI’s Identification Division are dispatched to assist in identifying the bodies of the victims (Barnes, 2011).
- 1943- Dr. Harold Cummins of Tulane University publishes a book he coauthored with Charles Midlo entitled Fingerprints, Palms and Soles – An Introduction to Dermatoglyphics, which is based on his extensive research on the fetal development of volar pads and its relationship to the morphology of friction ridge skin (Ashbaugh, 1999).
- 1952- Dr. Alfred Hale, also from Tulane University and an associate of Cummins, publishes his thesis “Morphogenesis of the Volar Skin in the Human Fetus”, which is based on his extensive research into the differential growth of friction ridges during fetal development (Ashbaugh, 1999).
- 1953- Salil Kumar Chatterjee, a scientist from Calcutta, India, publishes his book Finger, Palm and Sole Prints. In 1962 Chatterjee also publishes an article titled “Edgeoscopy”, for which he is most recognized, which describes his theory of using ridge edge shapes to supplement fingerprint identifications (Ashbaugh, 1999).
- 1976- Dr. Michio Okajima of Japan publishes his paper “Dermal and Epidermal Structures of the Volar Skin”. Okajima is most notable for his contributions in the study of incipient ridges (Okajima, 1975).
- 1991- Dr. William Babler of Marquette University Wisconsin publishes his paper “Embryologic Development of Epidermal Ridges and Their Configurations” which is based on his work involving the prenatal relationship between the epidermal ridges and bone dimensions in the hand. The paper also reviews the literature of prior research involving embryologic ridge development (Ashbaugh, 1999).
Another prominent modern figure responsible for the advancement of the science of fingerprint identification is David R. Ashbaugh. Ashbaugh, a Certified Forensic Identification Specialist and retired Staff Sergeant with the Royal Canadian Mounted Police, has spent 28 years conducting extensive research in the field of fingerprint identification, specifically in the development, formation and analysis of the friction ridges of the skin (Evidence Technology Magazine, 2007). Through his research, he has expanded on the analysis and comparison processes that are involved in the evaluation of friction ridge characteristics to include the ridge units themselves; i.e., the intrinsic ridge formations, which are relative to size, shape and the positioning of pores and are unique to the individual ridge units themselves (Ashbaugh, 1999)
The term “Ridgeology” coined by Ashbaugh in 1982 comprises the analysis of these details, also known as third level detail. He discusses this research in his book Quantitative-Qualitative Friction Ridge Analysis – An Introduction to Basic and Advanced Ridgeology, which was published in 1999. Ashbaugh is also credited with the expansion of ACE (Analysis, Comparison, Evaluation), which now includes a fourth and final step, verification. ACE-V is the scientific methodology that is used by fingerprint examiners today (Evidence Technology Magazine, 2007).
Theory
It has been stated many times that fingerprints are unique. This premise is what makes fingerprint identification superior to other methods of identification (FBI, 1984). If this is the case then how do we know that fingerprints are in fact unique? In theory we do know because of the thousands of fingerprint examiners conducting “scientific experiments” each and every time they perform analysis in case work and in the millions of searches being conducted through AFIS and IAFIS (Integrated Automated Fingerprint Identification System) (Champod & Evett, 2001).
In order to further understand the theory of uniqueness, scientists have been conducting extensive research for years, specifically involving the biological development of friction ridges in fetuses; and indeed, this type of research is ongoing today. David Ashbaugh is one the researchers who has been instrumental in the effort of bringing this information to the forefront of the fingerprint community. His research has led to the advancement of forensic science through the support of previous fingerprint studies conducted within the field of biological science (Ashbaugh & Houck, 2005).
In his book Quantitative-Qualitative Friction Ridge Analysis – An Introduction to Basic and Advanced Ridgeology, Ashbaugh discusses the growth and recession of the volar pads (bulbous protrusions) in the hands of the developing fetus. Volar pad growth begins at about the sixth week of the gestational period and continues to grow as they begin to swell, and then suddenly begin to recess at around the twelfth week, when the friction ridges begin to develop in the basal layer of skin. This swelling in the volar pads as well as genetics, determine the pattern type (Ashbaugh, 1999). Other factors including maternal diet, developmental stressors and the movements of the fetus affect the ridge path deviations or breaks in the friction ridges. All of these random biological events, which occur during the critical stage of fetal development, contribute to the formation of the individual features which make fingerprints unique (Wertheim & Maceo, 2002)
There has also been validation studies conducted for establishing the individuality between twins which further exemplifies the uniqueness of fingerprints. In one particular study, 3,000 pairs of fingers from identical and fraternal twins, including all finger types, were compared for level 1 (pattern type) and level 2 (minutiae) detail. The conclusion held that although pattern types were often similar among twins, the minutiae or individual characteristics within the patterns were indeed unique (Srihari, Srinivasan & Fang, 2007). Other fingerprint studies on genetic variability, which focus on the heritability between variables of race and gender (Singh, Chattopadhyay, & Garg, 2005), as well as the determinacy of certain genetic disease risk factors have been recently published (Kahn, Ravindranath, Valdez, & Narayan, 2001) .
Methodology
ACE-V is the accepted scientific method practiced by fingerprint examiners today and is currently the only method recognized and endorsed by the International Association for Identification and the Scientific Working Group on Friction Ridge Study and Technology (SWGFAST) as a valid scientific standard for fingerprint examination. ACE-V is an acronym for analysis, comparison, evaluation and verification, which are the four steps involved in the examination process. Analysis (A), the initial stage, is the assessment that is conducted of an impression to determine its suitability for comparison. This assessment utilizes three levels of friction ridge detail. The first level consists of the general class features or pattern classification of the impression; i.e., loop, arch or whorl, as well as the overall ridge flow. The second level consists of the individual characteristics present within the impression and the third level encompasses the aspects of “Ridgeology”, i.e., the shape and/or size of the individual ridges, positioning of the pores, etc. It is at the analysis stage that the value and sufficiency of an impression is determined. Once sufficiency and/or classification is established, the examiner moves on to the comparison (C) stage, which involves the visual observation of the similarities and/or differences in correlation with the sequence and spatial relationship of the characteristics present within the two friction ridge impressions. At the evaluation (E) stage, a conclusion is established through the cumulative data gathered in both the analysis and comparison stages in which three conclusions can be drawn: (1) Individualization– the determination that “two friction ridge impressions originated from the same source”, (2) Exclusion– the determination that “two friction ridge impressions originated from different sources” and (3) Inconclusive– the determination which “result[s] in the inability to reach either an individualization or exclusion decision”. Verification (V), the final stage, is the replication of the ACE method by a second examiner who is deemed qualified to objectively confirm or reject the conclusion made by the primary examiner (SWGFAST, 2002).
Prior to the use of ACE-V, the only standard in practice was the “twelve point rule”. This standard required that all conclusions of identification be predicated on a minimal numerical threshold of twelve identifying and sequential ridge characteristics within two friction ridge impressions. It was falsely believed that the absence of a numerical threshold somehow invalidated the process and deemed it “unscientific”; however, the rule did not take into consideration the totality of all analytical, comparative, and evaluative processes involved, but instead placed unsubstantiated limitations on the examiner’s evaluative conclusion (Champod & Evett, 2001).
William F. Leo, a certified latent print examiner and author states: “In the guise of quality control, standards based solely upon the quantity of characteristics reduce an examiner to a technician more adept at ciphering than exercising scientific judgment” (1994). For example, under the minimum point standard, a latent print with only an area of “open fields” or an area containing no ridge path deviation, would technically be determined “unidentifiable”; however, an examiner with specific knowledge and training can logically deduce that the absence ridge path deviation is as equally unique as its presence. Because of the extent of the quantitative-qualitative method of analysis and the varying complexity of each impression, it is impossible to assume that all identifications be limited to the same cookie-cutter like process (Champod & Evett, 2001). “The flaw in the use of any numeric standard for friction ridge identification is its inability to account for all the observations made and the examiner’s ability to evaluate this information” (Leo, 1994).
Another argument against the “point standard” is the fact that not all agencies had the same numerical standard of twelve points. Some agencies mandated that as little as eight points or even six points were sufficient (Champod & Evett, 2001). Where is the valid scientific basis for this pre-determination? It was also theorized that this practice would prevent errors in identification. This analogy seems absurd since within any situation where a human is involved the possibility for error will always exist. It is through verification that errors, if any are made, may be identified and corrected (Ashbaugh & Houck, 2005).
To resolve the inconsistencies that the point standard presented within the fingerprint community the IAI formed a committee, and through a three year study came to a decision on the matter; and in 1973, a report from these findings state: “‘[There is] no valid basis [that] 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’” (Ashbaugh & Houck, 2005). Needless to say, there are still agencies that adhere to a point standard. This is an issue that will probably continue to be argued for years to come.
However, more recently there has been a focus on quantitative research involving the development of statistical probability models and likelihood ratios for the identification of latent prints. One particular study, “Computation of Likelihood Ratios in Fingerprint Identification for Configurations of Any Number of Minutiæ”, seeks to obtain a more robust and quantifiable method for assigning values to friction ridge minutiae, known as Level 2 characteristics. The research design for this model takes a more objective approach in validating the latent print examination process by using Level 2 characteristics; i.e., ridge endings, bifurcations and dots, and assigning them a numerical value based on triangular positioning, feature vector, frequency and pattern type. A numerical scale is then calculated based on the sum of each value within a particular minutiae configuration containing n number of features. Variability is also assessed by assigning values for both distortion and background noise, calculating their mean values and compiling the sums into a mean value set σ and a standard deviation set µ. Lastly, an overall likelihood ratio (LR) is calculated by multiplying the sums of these values, where the total sum (LR1) is the numerator and the total sum of random sources containing n number of close but non-matching minutiae configurations (LR2) is the denominator (Neumann, et al., 2007).
The authors proposed this probability model in light of the current trend to strengthen the validity of the latent print identification process, which resulted due to a recent influx in court challenges and federal legislation calling for reforms in forensic science. Up to this point, the latent print discipline had been seriously lacking in statistical research, specifically studies committed to developing computational models which could determine the probability ratios for minutia configurations in latent print impressions. The authors in this study tested their model on a sample of 686 ulnar loops and 204 arches. The results were promising, showing low a low false positive rate and the likelihood ratio (LR) power of the model significantly increasing with the number of minutiae. Additionally, within a significant percentage of the cases the LR’s indicated a correct identity a source, even in cases where configurations contained few minutiae. This model is an improvement from previous studies in that it takes into account finger distortion; and by incorporating radial triangulation method, the model is also more efficient because can measure the spatial relationships of minutiae (orientation) without imposing probabilistic assumptions (Neumann, et al., 2007).
Another study titled “Pilot-study: A statistical analysis of the ACE-V methodology – analysis stage”, conducted by Glen Langenburg of the Minnesota State Crime Lab, takes a quantitative approach toward the validation of the ACE-V methodology. Langenburg designed this pilot-study as the prototype to a series of studies designed to deconstruct and examine the various aspects of the ACE-V methodology, which is the examination standard used by latent print examiners today. The intended goal for this series of long term research is to gain insight into each stage of the methodological procedure by collecting data and to the gauge the effectiveness of the methodology with the intention of making improvements in examiner training and possibly within the method itself (Langenburg, 2004).
This first study examines the Analysis stage of the ACE-V methodology. It is designed to examine only the quantitation of minutiae during the analysis phase of fingerprint examination. A test group consisting of 24 latent print examiners and trainees with varying levels of experience and a control group consisting of 50 participants with no training or experience in latent print examinations participated in the study. Both groups were given a survey packet which included a worksheet consisting of 12 print impressions (2 inked control prints and 10 latent prints), an instruction sheet for counting minutiae, an enlarged copy of one of the 10 latent prints and a four-page survey consisting of 30 questions (Langenburg, 2004).
The objectives for the study were to determine: (1) the mean responses and variances between the test group and the control group, (2) whether significant variances between the latent print examiners and the trainees (if any were observed), could be attributed to factors involving information obtained in the survey, (3) which of the minutiae was most frequently observed and (4) whether participants in both groups observed features which were not minutiae (Langenburg, 2004).
The results of the study drew the following conclusions: (1) there was no significant variance in the mean response of minutiae reported among the test group, (2) there was a significance in variance between the test group and the control group for the mean response of minutiae reported, (3) the mean response of minutiae reported by the test group was nearly doubled that of the control group and (4) the test group marked more minutiae correctly than the control group who tended to mark more false minutiae (Langenburg, 2004).
Tools of the Trade
For years the only tools fingerprint examiners had at their disposal were their eyes and the trusted magnifying loupe and pointers. Searches were conducted manually using the Henry classification system which meant tireless searching through hundreds even thousands of inked fingerprint cards. Since the last 100 years, technology has allowed the science to flourish by incorporating the first computerized databases capable of searching through millions of fingerprints. This ability caused a significant increase in the total percentage of fingerprint identifications. This increase aided in the solving of numerous criminal cases that would have possibly gone unsolved in the past (U.S. Dept. of Justice – FBI, 2011).
These computer systems known as AFIS (Automated Fingerprint Identification System) and the FBI’s IAFIS (Integrated Automated Fingerprint Identification System) made their debut in the early 90’s allowing the fingerprint examiner to search digitally scanned images. These scanned images are captured using Livescan computers that use lasers to scan the surfaces of the fingers and palms then transferring them to an automated file (U.S. Dept. of Justice – FBI, 2011).
This became a wonderful tool to the fingerprint examiner who could view these scanned fingerprints on a computer screen without excess strain to the eyes. Other integrated features allow for the enhancement of latent prints which are often times fragmented and distorted. The image could be magnified as well as enhanced in quality. For an agency that acquired this system there would be no more straining through magnifying loupes and time consuming searches through manual files (Evidence Technology Magazine, 2008).
There have been several upgrades in the past few years, each time adding new features and search capabilities. One such capability that is currently in the works is the interoperability between local and state databases. Currently, local operating systems within each state can only search that state’s database or search the FBI’s database IAFIS. For example, state X could not search state Y’s database and vice versa but with interoperability the systems could be linked to search other databases. This would further expand the examiner’s search thus increasing the probability of an identification being made (Evidence Technology Magazine, 2008).
The Fingerprint Examiner
The role of the fingerprint examiner is one of great importance. Without fingerprint examiners many criminals would go unidentified, criminal cases would possibly go unsolved and the missing and the dead could remain anonymous. Although these are just a few of the functions performed by fingerprint examiners, their work does not stop there. Not only does the examiner have to be highly skilled and expertly trained, he/she has to be proficient. There is no room for error in this discipline (Jones, 2007).
The fingerprint examiner today is more knowledgeable and professional than in past decades. Examiners must continually strive to increase their skill, knowledge, training and experience and are invariably exposed to rigorous testing and peer review. Examiners currently entering the field have more formal educations and are expected to have knowledge and understanding of other sciences such as chemistry and physics. Groups such as the IAI and SWGFAST are strong forces in setting the guidelines with which examiners should follow and they continue to encourage research and professional growth (James & Nordby, 2005).
More than ever before today’s fingerprint examiners are increasing being challenged in the court room and must continually remain current with the latest research and training in order to survive the cross-examination of their expert testimony. In an article by Christophe Champod and Ivan Evett that was published in the Journal of Forensic Identification, the authors make reference to the ability of the fingerprint community and its practitioners to uphold the discipline’s “scientific status”. Additionally, the article is right on par with what is happening in the field today when it suggests it is the responsibility of its practitioners to become more exposed to training in the sciences and in scientific testing protocols in order to gain back its credibility within the science world (Champod & Evett, 2001) .
New Precedents Create New Challenges
There were many early pioneers in the study of fingerprints, most of whom were doctors and scientists whose studies in the biological development of friction ridge skin led to the discovery of fingerprint identification. From these early discoveries, and through the continued research and current innovations in science and technology, fingerprint identification has evolved to become one of the most recognizable and efficient forms of human identification in forensic science today. However, along with these modern advancements, so too have come its challenges.
In 1993 one of those challenges came in the form of a Supreme Court ruling, not as a result of an appealed criminal court conviction but through an appeal on a summary judgment made by plaintiffs in a civil litigation suit against the major medical drug manufacturing corporation Merrell Dow Pharmaceuticals (U.S. Supreme Court, 1993) . The decision to appeal the judgment arose as a result of conflicting expert scientific and medical testimony on both sides which cast light on the obvious question “what criteria determines whether a method or practice is (a) scientific and (b) valid?”, eventually making its way up to the Supreme Court to decide. Subsequent to its now infamous ruling in the case known as Daubert v. Merrell Dow Pharmaceuticals (1993), the Supreme Court successfully set a new precedence for the admissibility of expert scientific testimony and also raised the bar in forensic criminal cases. Though its standard applies to all expert scientific testimony, its implementation has since elicited a stream of attacks by critics who question the validity of forensic science in general, particularly those applications used in forensic identification; more specifically, fingerprint and latent print identification (Jones, 2007).
Meeting the Daubert Challenge
The criterion established by this Supreme Court ruling imposes the implementation of four specific guidelines in measuring the admissibility of scientific or technical expert testimony, which are: (1) Has the theory/technique been tested and has it been subjected to peer review and/or publication and validation? (2) Is there a known or potential error rate? (3) Are standards maintained which govern the operation of the method or technique? (4) Is it generally accepted within the relevant scientific community? The judge acting in the role as gatekeeper must make this determination using these guidelines (U.S. Supreme Court, 1993).
It is evident from its documented history through over 100 years of research, which has served as a cornerstone in the validity of the science, that fingerprint identification more than sufficiently meets the Daubert requirements; however, the goal in writing this paper is to further substantiate this conclusion by deconstructing each of the four standards and citing the supporting documentation relevant to the discipline and the science.
(1) Theory- permanence and uniqueness: the basic premise of fingerprint identification, validation studies. Technique– the scientific methodology: ACE-V.
- 1892- Galton publishes his book Finger Prints establishing the theory of permanence and uniqueness (Galton,1892).
- 1883- Dr. Arthur Kollman conducts primate studies on the embryological development of friction ridge skin forming a link between volar pad development and friction ridge growth (Barnes, 2011).
- 1897- Hawthorne Wilder publishes his article “On the Disposition of the Epidermic Folds Upon the Palms and Soles of Primates” and proposes that friction ridge patterns in primates were associated with volar pad development. Sets the foundation for the premise of evolutionary development (Barnes, 2011).
- 1904- Inez Whipple Wilder publishes her paper “The Ventral Surface of the Mammalian Chiridium” which establishes the theory of evolutionary development in friction ridge skin (Barnes, 2011)
- 1914- Edmond Locard publishes his paper “The Legal Evidence by the Fingerprints” which focused on the use of pores in the identification process (Barnes, 2011).
- 1943- Dr. Harold Cummins publishes book Fingerprints, Palms and Soles – An Introduction to Dermatoglyphics, based on the fetal development of volar pads and its relationship to the morphology of friction ridge skin (Ashbaugh, 1999).
- 1952- Dr. Alfred Hale publishes his thesis “Morphogenesis of the Volar Skin in the Human Fetus”, based on differential growth of friction ridges during fetal development (Ashbaugh, 1999).
- 1953- Salil Kumar Chatterjee publishes his book Finger, Palm and Sole Prints. In 1962 Chatterjee also publishes an article titled “Edgeoscopy”, describes his theory of using ridge edge shapes to supplement fingerprint identifications (Ashbaugh, 1999).
- 1976- Dr. Michio Okajima publishes his paper “Dermal and Epidermal Structures of the Volar Skin”. Notable for his study of incipient ridges (Okajima, 1975).
- 1991- Dr. William Babler publishes his paper “Embryologic Development of Epidermal Ridges and Their Configurations” based on his work involving the prenatal relationship between the epidermal ridges and bone dimensions in the hand (Ashbaugh, 1999).
- 1999- David Ashbaugh publishes his book Quantitative-Qualitative Friction Ridge Analysis – An Introduction to Basic and Advanced Ridgeology. Discusses ridgeology and the ACE-V methodology.
- 2001- Genetic studies on the determinacy of certain genetic disease risk factors (Kahn, Ravindranath, Valdez, & Narayan, 2001)
- 2005- Studies on genetic variability, which focus on the heritability between variables of race and gender (Singh, Chattopadhyay, & Garg, 2005),
- 2008- Twin studies conducted for establishing the individuality between the fingerprints in twins (Srihari, Srinivasan, & Fang, 2008)
(2) Error rate- CTS proficiency testing and scientific studies.
- 2004- Glen Langenburg designs pilot study for the statistical analysis of the ACE-V methodology (Langenburg, 2004).
- 2007- Statistical research studies on developing likelihood ratios in fingerprint identification. The research design for this model takes a more objective approach in validating the latent print examination process (Neumann, et al., 2007).
(3) Standards- SWGFAST, International Association for Identification (IAI).
- 1915- Harry Caldwell forms the International Association for Identification (IAI) (theiai.org, 2011).
- 1973- The IAI conducts research to invalidate the use of point standards. “‘[There is] no valid basis [that] 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’” (Ashbaugh & Houck, 2005).
- 1982- David Ashbaugh coins the term “ridgeology” to describe the use of third level detail in fingerprint identifications (Ashbaugh, 1999)
- 1998- SWGFAST is formed by the FBI (SWGFAST, 2011).
(4) General acceptance- history and timeline: over 100 years of research in the scientific community. Court precedents.
- 1911- People vs. Jennings. Appellate court recognized fingerprint identification as a science and expert testimony should be deemed appropriate in supporting the jury’s understanding of fingerprint evidence (Barnes, 2011).
- 1911- People vs. Crispi. The first judicial conviction in the U.S. determined solely from evidence involving the identification a latent fingerprint (Barnes, 2011).
- 1939- The Washington County Supreme Court upheld the decision on a habitual offender conviction in State v. Johnson, 1939. Upheld the practice of fingerprint identification using certified copies of the defendant’s prior conviction records (Barnes, 2011).
- 1939- The sinking of the USS Squalus. Fingerprints were used to identify disaster victims (Barnes, 2011).
- 1940- An appellate judge in Hamilton Texas upheld a conviction that was based on the identification of a latent fingerprint. Judge proclaimed there was sufficient proof in the classification and identification of thousands of fingerprints conducted in the U.S. to hold that fingerprints were unique (Barnes, 2011).
- 1940- The FBI Disaster Squad is formed in response to the Pan Am Airliner crash in Lovettsville, Virginia. Fingerprints were used to identify disaster victims (Barnes, 2011).
Conclusion
Today, the science of fingerprint identification has become one of the most formidable assets in the field of forensics. It has developed over time from a mere curiosity into the vast and dynamic discipline it is today; and though it is one of the oldest and most reliable methods of personal identification, it’s validity as a scientific application has continually fallen under attack. Issues which arose as a result of Supreme Court cases such as Daubert vs. Merrell Dow Pharmaceuticals, Inc., call into question the reliability of fingerprint identification and lay doubt about the scientific validity of forensics as a whole. However, throughout history fingerprint identification has been established time and again as a tried and true practice; and in the end, so too shall forensic science prevail. Through its establishment as a pioneer in the vast field of forensics, the dedicated research of educated professionals and its innovation into the advancements of technology, fingerprint identification will continue to evolve and to persevere as it continues to gain credibility within the science world.
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