Fingerprints boast a long history in their use for individual identification. The uniqueness of individual fingerprints makes them one of the best individualizers, and therefore they are used as identification tools in program enrolment, identification documents, and most importantly in investigating crimes (Cherry & Imwinkelried, 2006). Interestingly, although fingerprint identification has been employed in crime solving for a long time, its reliability has not undergone comprehensive testing; neither the uniqueness of individual fingerprints has been fully verified (Mnookin, 2003; Schwinghammer, 2005). Such holes in the credibility of fingerprints have caused criticism over the use of fingerprints in personal identification and crime investigation. Critics posit that without comprehensive tests to prove numerous assumptions about the uniqueness of fingerprints, the credibility of such identification tool is in question (Mnookin, 2003). However, despite these negative judgements, fingerprints continue to play a major role in individualized identification, security, and crime solving. Galton’s assertions of the uniqueness of fingerprints in the 19th century, when he developed the first system of fingerprint classification and identification, remain the supporting claim for the use of fingerprints as the unique individualizers today (Cherry & Imwinkelried, 2006). Therefore, despite some negative judgements about the validity of fingerprints, they remain the most effective and reliable means of individual identification; and with recent advances in technology, fingerprints provide information that transcends identification alone and discloses important data instrumental in solving crimes.
Although the study and employment of fingerprints particularly in crime solving are relatively recent phenomena, there are reports of the use of fingerprints in the ancient era. According to Schwinghammer (2005), archeologists have unearthed reports indicating the use of handprints or fingerprints as signatures in Ancient Egypt, as well as in the second century B.C.E. in China. Back then in 1303, writing about the uniqueness of fingerprints and their use as signatures, a Persian historian asserted, “experience shows that no two individuals have fingers precisely alike” (Schwinghammer, 2005, p. 273). Despite such early assertions about the uniqueness of fingerprints, their use as a method of identification did not catch on in Europe until the end of the 19th century.
The need for an alternative method of identification came in mid-19th century Europe following increased rates of crime. Specifically, recidivist crime became a problem exacerbated by the evolving mobile urban society, which then gave individuals anonymity. The situation was convenient for criminals, giving them more opportunity to commit crime, while at the same time making it difficult for law enforcement to identify repeat offenders (Schwinghammer, 2005). Thus, even though new reforms in criminal law punished repeat offenders sterner than first-time offenders, there was a need for a system of identification: one that would make it difficult for recidivist criminals to escape justice by providing false names (Cherry & Imwinkelried, 2006; Schwinghammer, 2005).
At the same time, photographic technology helped in identification of notorious criminals through circulation of pictures of rogues. However, the sheer number of pictures rendered the system haphazard and time-consuming (Schwinghammer, 2005). The pictures came at a time when the British police was recording criminals’ tattoos, scars, and distinctive identification marks. The British system, however, faced challenges including presentation of information in a format useful for identification (Schwinghammer, 2005).
The Bertillon system developed by French official Alphonse Bertillon in 1884 offered a reprieve to the law-enforcement community. The official had perfected an anthropometric system, which recorded the exact measurements of eleven body parts enabling identification of the individual (Schwinghammer, 2005). The system, although complicated, was accurate and adopted by a dozen countries. However, the system faced accuracy issues as it moved away from its originator in Paris (Schwinghammer, 2005).
The development of fingerprints as a recognized method of identification began in 1859 with William Herschel who had a hobby of collecting his friends’ fingerprints. Herschel’s scrutiny of the fingerprints he had collected convinced him in their uniqueness (Schwinghammer, 2005). Moreover, in his continued collection of fingerprints, Herschel discovered that they did not change over time. Hershel shared this information with Francis Galton so that the two originated the premises of fingerprints as unique and permanent, as well as the science of fingerprint identification (Schwinghammer, 2005). Furthermore, Henry Faulds began investigation into the uniqueness of fingerprints and the use of 10 fingerprints in identification of criminals. Moreover, even Mark Twain wrote in his published story about the use of thumbprints as the “infallible French system”, that is, a unique proof of identity (Schwinghammer, 2005).
One of the first countries to use fingerprints for identification was Great Britain that employed this method of recognition in India. The British used fingerprints to identify repeat offenders on their return to custody in India, in addition to discovering the use of fingerprints in criminal investigations (Schwinghammer, 2005). The first investigation, and perhaps the case that brought fingerprints into courthouse as evidence, involved a murdered man whose servant had been released from custody recently. In their investigation, the police found a bloody fingerprint fragment which matched the servant’s fingerprint (Schwinghammer, 2005). Although there was no expert to verify a match between the two sets of fingerprints, the judge and the assessor examined them to conclude that they belonged to the suspect (servant). Meanwhile, in the U.S., the first case that accepted the use of fingerprints as evidence involved Thomas Jennings accused of killing Clarence Hiller in 1901 (Mnookin, 2003). With four witnesses testifying for the prosecution that the fingerprints belonged to Jennings, the judge passed the ruling convicting Jennings of the murder of Clarence Hiller, therefore allowing fingerprints to make their foray into the criminal justice system as evidence in a crime (Mnookin, 2003; Schwinghammer, 2005).
The acceptance of fingerprints as a method of identification is based on the premise of their uniqueness. In developing the system of classification and identification of fingerprints, Galton claimed that “the odds of two individual fingerprints being the same are 1 in 64 billion” (Cherry & Imwinkelried, 2006, p. 55). The uniqueness of the prints consists largely in their patterns, which include loops, whorls, and arches. Thus, although collected fingerprints may feature any of the three patterns, the uniqueness of the loops, whorls, or arches helps in identification.
Whorls, loops, and archers are merely different types of patterns unique to individuals; however, in the identification and examination of fingerprints, experts examine specific details, including the patterns and ridge details made by the fingers. Fingerprint identification specifically refers to the scrutiny of similarities and variations in the fingers’ patterns and ridges (Schwinghammer, 2005). The shape of ridgelines, ridge details, and sweat pores are distinct categories of details analyzed during fingerprint examination. First of all, in examining the shape of the ridgelines, experts examine the prints identifying them according to the patterns they make as arches, whorls, or loops.
After that, ridge details constitute the second level of details used by examiners in comparing fingerprints to make identification. The ridge details are the points along the friction-ridge lines, which detail any unusual pattern (Schwinghammer, 2005). The ridge details, therefore, help in identifying bifurcating ridge points and terminated ridge points. Schwinghammer (2005) informs that according to the FBI, human fingertips, on average, have 75-175 ridge details. The ridge details are instrumental in identification of fingerprints, as examiners use them to compare known fingerprints to latent fingerprints. A number of corresponding ridge details required for identification varies among jurisdictions. Therefore, while some jurisdictions will require a minimum of 30 corresponding ridge details, others such as the jurisdiction of Italy will require 16, while that of Sweden demands seven. For the U.S., however, identification is subject to the examiner’s decision, with convictions obtained with fewer than 15 ridge details matched as points of comparison (Schwinghammer, 2005).
Finally, sweat pores make the third type of fingerprint components identified and analyzed during examination of prints. Just like the patterns, the sweat pores feature unique placement on the finger. The size, shape, and location of the pores therefore offer details for matching and individualization. According to Schwinghammer (2005), examination of the pore placement and spacing is more precise as a method of identification.
It is worth mentioning that the process of fingerprint collection and identification largely depends on availability of fingerprints in the database. Matching known fingerprints to latent fingerprints helps in identification of the suspect. Known fingerprints collection involves taking the entire ridge surface of the fingertip and recording all the prints on the hand. Latent prints, which are basically fragments of fingerprints left by body fluids, oil residue or sweat at the crime scene, are collected using dusting, photography, or superglue fuming. Through these methods of latent prints collection, forensic experts can later match suspect’s known prints to the latent fingerprints found at the crime scene. Having access to known fingerprint databases, law enforcement agencies can easily run computer analyses of the latent prints, match them with the known fingerprints, and, consequently, convict a suspect (Cherry & Imwinkelried, 2006; Mnookon, 2003; Schwinghammer, 2005).
As aforementioned, Galton’s collection and examination of his friends’ fingerprints helped affirm the fact that fingerprints are not only unique to an individual but also permanent (Cherry & Imwinkelried, 2006). The premise of uniqueness and permanence, therefore, helps forensic science in identification of suspects. Following Galton`s premise about “the odds of two individual fingerprints being the same are 1 in 64 billion”, studies into fingerprints till the present date have not stumbled upon two people with the same fingerprints, including identical twins who are not only physically but also genetically identical (Cherry & Imwinkelried, 2006, p. 55; Cherry & Imwinkelried, 2006). Moreover, fingerprints’ uniqueness goes beyond similarities in the patterns of the prints to only slight similarity of any two prints from the same individual. The fact that no single person has identical fingerprints on multiple fingers supports the premise about the uniqueness of fingerprints and, therefore, explains its continued use as an identification method despite negative judgements of some critics.
As it has already been mentioned, aside from their uniqueness, fingerprint patterns are characterized by persistence and permanency. Thus, despite growth, wear and tear of the old skin and its replacement by new skin cells, the pattern of fingerprints remains essentially the same. In other words, new cells are formed to fit in the existing unique template outlined by the friction ridge, therefore maintaining the same matchless pattern. Moreover, even in instances of deep damage to the pattern of the print, the resulting arrangement after the damage is not only unique but also persistent and permanent throughout the individual’s life. Obviously, such characteristics as persistence and permanence become another reason for using fingerprints as a safe and secure method of investigation and recognition (Oorschot & Jones, 1997).
However, alongside proponents of the use of fingerprints for personal identification, there are opponents of this method of recognition. Critics’ objection to the use of fingerprints for identification, and particularly for its use in forensics, is the claim that it lacks validity. This claim comes from the fact that fingerprint identification methods have not undergone purely scientific tests (Mnookin, 2003). Besides, in their dissent against fingerprints as admissible evidence, critics continue to state that there are no peer reviews for fingerprint identification techniques, no standards or norms that control the operations, and no general acceptance of the identification process among the community of fingerprint identification experts (Mnookin, 2003).
Furthermore, critics support their standpoint by insisting that fingerprint forensic experts lack an objective standard for evaluation of two matching prints. The opponents continue to assert that there is no uniform approach to making any proven identification (Mnookin, 2003). The purpose of such claims is to poke holes in the use of fingerprints as forensic evidence, as well as to undermine the objectivity of the methods used for identification of fingerprints and the impartiality of examiners.
Nevertheless, despite the strong arguments of the opposition, advances in technology and particularly in forensic science have made tremendous contribution to the use of fingerprints for identification and forensic evidence. According to a study by Oorschot and Jones (1997), fingerprints provide more than just an identification tool for forensics. Through their study, Oorschot and Jones (1997) discovered that it was possible to generate genetic profiles from fingerprints. The study proves that fingerprints carry not only the identification marker of an individual but the genetic data as well. The authors discovered that it is possible to elaborate a genetic profile based on swabs taken from objects touched by an individual, therefore not only validating the use of fingerprints as forensic evidence but also providing a new tool for crime scene investigation (Oorschot & Jones, 1997).
Going beyond matching latent and known fingerprints and allowing to carry out genetic identification, advances in technology provide an opportunity of discovering other pertinent data about the suspects through their fingerprints. For example, with such new technology as spectroscopy used in forensic laboratories, forensic scientists can find traces of other substances, however small, in latent fingerprints on or within fingerprint ridges (Morelle, 2014). Vaporizing the sample and passing it through electric and magnetic fields helps the forensic scientists in identification of molecules within the sample based on different behavior of particles of distinct masses under the conditions provided. The information gathered from the process is diverse and instrumental for investigation. According to Morelle (2014), through such process it is possible to identify whether the suspect is male or female, specify whether the suspect used or is currently using drugs, and reconstruct ingested substances to discover the food the person had been eating before committing the crime. Even more is that the exogenous substances collected from the fingerprints can help shed light on the suspect’s lifestyle and their activities, thus facilitating the investigation process. Moreover, since all these processes and methods are verifiable, they give fingerprinting not only the validity and credibility critics say it lacks, but also the accuracy needed for criminal investigation, and most importantly admissibility as evidence in a court of law (Morelle, 2014).
It is worth mentioning that apart from addressing the issues raised by the opponents of the use of fingerprints for identification, continuous improvements of technology help fingerprint experts confront the challenge of investigating unusual crimes, because criminals are continually improving their ways of committing crime and avoiding capture (Morelle, 2014). The advances of fingerprinting in DNA and identification of the suspect’s lifestyle provide an extra layer of reliability for fingerprinting as a method of suspect identification and evidence in court. As a result, despite several negative judgements, examination of fingerprints remains one of the most credible and effective ways of personal identification.
To sum it up, the evolution of technology makes it possible to not only identify suspects by their fingerprints but also generate their DNA profile and describe their lifestyle via fingerprinting. Such achievements increased the credibility and reliability of fingerprints, quelling critics’ protests against the reliability of this method of suspect identification. Continuous advancements of technology only bolster the reliability of fingerprints as forensic evidence for identification of suspects. Therefore, despite some negative judgements undermining the effectiveness of fingerprinting for crime scene investigation, forensic science has already proved the reliability of this tool for suspect recognition. Moreover, with new discoveries in this field, fingerprinting has the potential to be officially recognized as a scientifically proven method of suspect identification.
Cherry, M., & Imwinkelried, E. (2006). How we can improve the reliability of fingerprint identification. Judicature, 90(2), 55-57. Retrieved from search.proquest.com/docview/274569115? accountid=1611.
Mnookin, J. L. (2003). Fingerprints: not a gold standard. Issues in Science and Technology, 20(1), 47-54. Retrieved from search.proquest.com/docview/195919066? accountid=1611.
Morelle, R. (2014). Fingerprints give police new clues for solving crime. BBC. Retrieved from www.bbc.com/news/science-environment-26668838.
Oorschot, R. A. H., & Jones, M. K. (1997). DNA fingerprints from fingerprints. Nature, 387(6635), 767. doi: http://dx.doi.org/10.1038/42838.
Schwinghammer, K. (2005). Fingerprint identification: how “the gold standard of evidence” could be worth its weight. American Journal of Criminal Law, 32(2), 265-289. Retrieved from search.proquest.com/docview/206271976?accountid=1611.