Scientist Special: Galton, Herschel & Faulds – The Competing Pioneers of Fingerprinting

Scientist Special: Galton, Herschel & Faulds – The Competing Pioneers of Fingerprinting

The use of fingerprints as a means of identification has been successfully implemented worldwide. But how did the idea of using these unique impressions in a forensic setting first come about? Many scientists are known to have been involved in the early research relating to fingerprinting, dating right back to the 1600s, but Sir Francis Galton and William Herschel are widely recognised as the real pioneers of forensic fingerprinting.

However the story actually begins with the work of another man: Henry Faulds. In the late 1880s, the Scottish physician was working in Japan in a number of roles, one of which caused him to be involved in various archaeological digs. During this time he first stumbled upon the uniqueness of fingerprints after discovering prints left behind by craftsmen in old pieces of ceramic pottery. This allegedly inspired his notion of using fingerprints to identify criminals, at which point he promptly published an article in Nature detailing his thoughts on the matter. In his manuscript, “On the Skin-Furrows of the Hand”, Faulds suggested the possibility of using fingerprints to identify individuals, however did not provide anything to support his theory other than the anecdotal evidence of his own use of fingerprints to identify the perpetrator of a break-in at his hospital. Back in the UK, Faulds shared his ideas with Scotland Yard, but they unsurprisingly had no interest in this somewhat unsupported theory. Incidentally, Faulds also shared his work with Charles Darwin. Although Darwin did not pursue the research himself, he did forward the information to his cousin, Francis Galton. At the time, nothing came of this interaction.

Shortly after Fauld’s publication in Nature, William Herschel, a British civil servant who was based in India at the time, soon published a responding letter in Nature claiming he had been using fingerprints as a means of identification for years. A very public argument over who should claim credit for this idea ensued between the two scientists which lasted for years, though the world paid little attention. There was quite simply no data to support the claims of the two men.

A couple of years later, Sir Francis Galton once again enters the picture. Now heavily involved in the field of anthropometry (the study of measurements of the human body), he began working with Herschel to gather the much-needed data necessary to support the theory of fingerprints as a means of identification. Galton’s research allowed him to collect thousands of fingerprints and ultimately conclude that fingerprints were in fact unique to the individual, could persist on a surface for years if not decades, and could be easily used to develop a system of storing and comparing prints. Galton presented his findings at the Royal Institution, sharing his and Herschel’s research in fingerprinting as a means of identification. Based on Galton’s work, the use of fingerprinting was finally considered by Parliament in 1894, and was soon implemented in criminal investigations. Galton and Herschel were now viewed as the original pioneers of forensic fingerprinting, whereas Faulds later spent years fighting to be recognised as the true founder, petitioning to academic journals, newspapers and even the Prime Minister.

In 1892, anthropologist Juan Vucetich made history by using fingerprint evidence to positively identify the culprit in a criminal case. When the children of Francisca Rojas were found murdered, Vucetich implicated Rojas when a bloody print allegedly proved she was the murderer. Since then, the study and use of fingerprints has been a fundamental aspect of forensic investigations worldwide.

References

Faulds, H. On the Skin-Furrows of the Hand. Nature, 1880, 22.

Stigler, S. M. Galton and Identification by Fingerprints. Genetics. 1995, 140(3), 857-860.

University of Glasgow. Henry Faulds. [online] Available: http://www.universitystory.gla.ac.uk/biography/?id=WH25214&type=P

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Determining the Age of a Fingerprint: Is It Possible?

Determining the Age of a Fingerprint: Is It Possible?

During the scrutinising examination of a crime scene, it is entirely plausible for dozens or more fingerprints and fragments of fingerprints to be recovered. Not at all surprising considering how often we touch endless surfaces in our day-to-day lives. Consider how many people might grasp the handle of a shop door in an average day. If that shop were to become a crime scene, how could one possibly distinguish between prints that had originated on the day of the crime and those deposited weeks or months ago? Is it possible to estimate the age of a fingerprint?

Firstly, a quick review of just what a fingerprint is. We all know fingerprints are a series of unique arches, loops and whorls left behind when we touch a surface. But people may be slightly less sure of what these deposits are actually composed of.

Although the composition of a fingerprint is somewhat complex, 95-99% of the deposit is simply water, which will typically readily evaporate. The remaining 1-5% is an intricate mixture of organic and inorganic compounds ranging from amino acids and fatty acids to trace metals. Chloride, potassium, sodium, calcium, hydrocarbons, sterols – the list goes on. A vast concoction of chemicals emitted through our skin and deposited whenever our fingertips touch a surface.

But what we didn’t know until recently, is that these deposited chemicals gradually move with time, and that this movement can be used to determine how long a fingerprint has been on a particular surface. Researchers from the National Institute of Standards and Technology recently stumbled upon this very fact (Muramoto & Sisco, 2015).

Fingerprint when freshly deposited (left) and after 72 hours (right). Credit: Muramoto/NIST

Fingerprint when freshly deposited (left) and after 72 hours (right).
Credit: Muramoto/NIST

Like many discoveries, the research itself was something of an accident. The NIST researchers were initially using analytical techniques to detect trace amounts of illicit substances present in fingerprints. In the process of this investigation, they noticed the movement of chemicals within the fingerprint over time. Fingerprints are made up of ridges and valleys forming unique patterns, the characteristic features that allow investigators to distinguish between prints deposited by different people. These features are imprinted in various chemicals when an individual leaves a print behind. However over time the chemicals composing the fingerprint begin to migrate, moving from the defined ridges of the fingerprint into the valleys, essentially blurring the details of the print.

The researchers focused on particular biomolecules, namely fatty acids such as palmitic acid. By depositing fingerprints on sterile silicon wafers and storing the samples under strictly controlled conditions for a period of time, scientists were able to clearly observe the migration of molecules using a technique known as time-of-flight secondary ion mass spectrometry (TOF-SIMS). After a period of only 1 hour after fingerprint deposition, the friction ridge patterns of the fingerprint were clearly visible with the fatty acid molecules under observation residing along the ridges of the print. However within 24 hours the molecules had diffused into the valleys, blurring the patterns of the fingerprint.

The research thus far has simply been conducted to prove the concept of fingerprint component migration for ageing fingerprints, but further work could investigate time effects on a greater scale and even differences in the migration of different molecules. Although the method is advantageous in that it does not depend on chemical changes in fingerprints, which can be very dependent on individual circumstances, further work would be warranted to establish how environmental differences could affect the rate at which this molecular movement occurs, including temperature and humidity effects as well as those caused by the deposition surface.

As intriguing as this research is, this is not the first time scientists have tried to devise a method of ageing fingerprints using chemistry. In fact, researchers have been attempting to accurately age fingerprints for decades. Research has focussed on the changes in the chemical composition of fingerprints over time. For instance, concentrating on a particular compound, such as cholesterol, and establishing the rate at which the concentration of that compound changes over time (Weyermann et al, 2011). Unfortunately many such studies have found changes in the chemical composition of fingerprints to be too variable and unpredictable, particularly when taking into account the differences between donors and the effects of different conditions. Other studies have attempted to determine the age of a fingerprint based on how well powder adheres to the ridges (Wertheim, 2003), by changes in fluorescence wavelength over time (Duff & Menzel, 1978), and changes in electrostatic charge with time (Watson et al, 2010). A vast array of scenarios have been studied intently.

A method of establishing the age of a deposited fingerprint has been at the forefront of latent print research for a long time, and is likely to continue. Although fascinating advances have been made, scientists are a long way from catching criminals by the age of a fingerprint.

References

Cadd, S. Islam, M. Manson, P. Bleay, S. Fingerprint composition and aging: A literature review. Sci Justice. 2015(55) pp. 219-238.

Duff, J. Menzel, E. Laser assisted thin-layer chromatography and luminescence of fingerprints: an approach to fingerprint age determination. J. Forensic Sci. 1978(23), pp 129-134.

Muramoto, S. Sisco, E. Strategies for Potential Age Dating of Fingerprints through the Diffusion of Sebum Molecules on a Nonporous Surface Analysed Using Time-of-Flight Secondary Ion Mass Spectrometry. Anal Chem. 2015(87) pp. 8035-8038.

National Institute of Standards & Technology. Who, What, When: Determining the Age of Fingerprints. [online] Available: http://www.nist.gov/mml/mmsd/20150824fingerprints.cfm

Watson, P. Prance, R. J. Prance, H. Bearsmore-Rust, S. T. Imaging the time sequence of latent electrostatic fingerprints. Proc. SPIE ‘Optics and photonics for counterterrorism and crime fighting VI, Toulouse, 7838, 783803-1-6, ISBN 9780819483560 (2010).

Wertheim, K. Fingerprint age determination: is there any hope? J. Forensic Identif. 2003(53), pp 42-49.

Weyermann, C. Roux, C. Champod, C. Initial Results on the Composition of Fingerprints and its Evolution as a Function of Time by GC/MS Analysis. J. Forensic Sci. 2011(56), pp 102-108.

Forensic Failures: The Shirley McKie Fingerprint Scandal

Forensic Failures: The Shirley McKie Fingerprint Scandal

In light of the recent FBI hair analysis outrage, it seemed appropriate to revisit an old classic in the history of failing forensic science. The Shirley McKie fingerprint scandal. Back in the 1990s, Shirley McKie was a police constable whose life, along with an important murder investigation, was essentially ruined due to mistakes made by forensic experts.

At the beginning of 1997, 51-year-old Marion Ross of Kilmarnock, Scotland was found murdered in her home, with suspicion quickly falling on David Asbury, a handyman who had previously carried out some work on the house. A number of fingerprints were recovered throughout the investigation, including one belonging to Asbury on a gift tag in the victim’s home. Further incriminating Asbury was a tin containing nearly £2,000 found in his house, which incidentally had the victim’s fingerprints on.

But by far the most controversial piece of evidence in this case was another fingerprint recovered from the crime scene which did not belong to neither the victim nor the suspect. A thumbprint was recovered from a doorframe at the murder scene and, according to the experts of the Scottish Criminal Record Office (SCRO), that thumbprint belonged to police constable Shirley McKie.

One might think the fingerprint of a police officer at a crime scene is nothing of great note, though perhaps some slightly sloppy police work, however that was not the case. Because in this instance, Shirley McKie adamantly denied that she had ever set foot in the victim’s house. So how did her fingerprint materialise at this crime scene? Well, it didn’t. McKie was telling the truth.

Unfortunately for McKie, her claims fell on deaf ears and she was subsequently suspended, fired and then arrested by Strathclyde Police in 1998 and charged with perjury (lying under oath), even though not one of the dozens of police staff involved could recall seeing her at the crime scene. A gruelling trial ensued, dragging both McKie’s reputation and life through the mud, along with the reliability of fingerprint evidence. Four fingerprint experts from SCRO concurred that the fingerprint belonged to McKie, the same experts who had identified the fingerprint found in Asbury’s home as belonging to the victim.

The fingerprint evidence in this case became something of a double-edged sword. If the latent print comparison conducted by the SCRO was accurate, Asbury could be reasonably named as the perpetrator but Shirley McKie would surely be lying about visiting the crime scene. Conversely, if McKie was truthful in her statement, then the fingerprint evidence was flawed and the evidence against the suspect useless. With the fingerprint identification being the only significant evidence incriminating Asbury, it naturally became a vital aspect of the case. At this point in time fingerprint evidence was perhaps viewed as an infallible gold standard in forensic science, and the jury agreed that the latent print evidence presented by the SCRO was accurate, thus Asbury was convicted and McKie assumed just as guilty.

Fingerprint comparison can be a subjective technique (www.clpex.com)

Fingerprint comparison can be a subjective technique (www.clpex.com)

Thankfully the investigation did not end there. Two fingerprint experts from the U.S. were called upon to offer their expertise, and both declared that the mysterious fingerprint found in the victim’s home did not belong to McKie. The SCRO experts had misidentified the fingerprints, although they stubbornly refused to admit to this. Furthermore, a member of the Scottish Parliament somewhat unusually invited fingerprint experts from around the world to examine the prints. 171 experts from numerous countries all reached the same conclusion – that the two latent prints did not match.

The fingerprint evidence was ultimately rejected and McKie was unanimously cleared of all charges. Perhaps too little too late for a woman who had lost her reputation and career. With the fingerprint evidence rejected and McKie’s name cleared, Asbury’s conviction was also overturned, with there being nothing more than mere circumstantial evidence linking him to the crime. So through this misinterpretation of fingerprint evidence, not only was Shirley McKie’s career ruined and the freedom of a potentially innocent man put on the line, but a murder investigation was left unsolved with little likelihood of ever finding the real killer of Marion Ross.

Over the years following this trial, a number of inquiries were conducted examining why this incident was allowed to occur in the first place. Through the public inquiry it was ultimately concluded that McKie had simply been the victim of human error and nothing more, though many argued at the time that there had been something of a conspiracy and cover-up. The inquiry called for competency training of analysts and for independent reviews to be carried out of any fingerprint evidence that is disputed, along with a prompt change in the way in which fingerprint comparisons were made in the first place.

Most importantly, it was recommended that fingerprint evidence should be viewed as opinion evidence only as oppose to the product of a scientific technique that can produce absolute answers, and that experts should not make claims with 100% certainty. This problem has been once again highlighted in the recent FBI scandal, in which hair analysis experts overstated the evidence, implying the analysis was far more reliable than it actually was. Members of the jury are unlikely to have any significant knowledge of forensic techniques utilised by experts, thus are hardly in a position to determine the reliability of the methods used. It is up to the expert to highlight just how dependable the evidence really is.

Although the Shirley McKie case offered a slight silver lining in highlighting the fallibility of forensic evidence, this is evidently a lesson that is yet to be taken onboard.

References

The Guardian. Fingerprint evidence ‘based on opinion rather than fact’. [online] Available: http://www.theguardian.com/uk/2011/dec/14/fingerprint-evidence-opinion-fact

McKie, I. A. J. ‘There’s name ever fear’d that the truth should be heard but they whom the truth would indite’ (Presentation given by Iain McKie to the Forensic Science Conference 2003. Sci Justice. 43 (2003), pp. 161-165.

University of Dundee. ‘Road map for reform’ of fingerprint practices to be developed at the Scottish Universities Insight Institute. [online] Available: http://app.dundee.ac.uk/pressreleases/2011/december11/fingerprint.htm

Caught Red-Handed: MALDI Mass Spectrometry & Bloodied Fingerprints

Caught Red-Handed: MALDI Mass Spectrometry & Bloodied Fingerprints

Most previous methods of establishing whether a fingermark at a crime scene contain blood are purely presumptive. The suspected fingermark, whether it be a print merely contaminated with traces of blood or an entire mark left in blood, will be subjected to tests which will aim to confirm or refute the presence of blood. However most existing presumptive tests suggest that it is a possibility the fingermark in question contains blood… but that it equally could be another similar substance that happens to produce a positive response with the test used. Thus is the limitation of any presumptive test – they can only give a possibility, not a definitive answer. Obviously not ideal during a forensic investigation.

Suspected bloodstains can be subjected to a wide range of tests to ascertain their composition. Blood may be visualised using alternative light sources, but this is a far cry from confirming its composition and in some cases (such as with the use of short-wave ultraviolet light) can even be destructive to DNA, thus obviously not ideal for the forensic examination of a blood sample. Spectroscopic techniques such as Raman spectroscopy have proved successful in potentially distinguishing blood from other biological fluids, though this has not been widely applied, particularly to blood in fingermarks. Chemical enhancement techniques have also been developed in the past, such as those that react with amino acids or haem-reactive compounds present to produce a colouring or fluorescence to enhance the blood. As successful as these methods may have been in the past, they are still only presumptive and cannot claim with any kind of near-certainty that any positive reaction produced is the result of blood and furthermore whether that blood is of human origin.

As a result of this, more confirmatory tests are needed.

More affirmative procedures do exist and are currently being developed. A particularly interesting method of detecting blood in fingermarks is using a technique known as MALDI MS. That is, Matrix-Assisted Laser Desorption Ionisation Mass Spectrometry. This relatively new analytical technique (relative to the history of mass spectrometry anyway) is most commonly applied to determining the mass of peptides, proteins and polymers, so is ideal for focusing on certain components of blood.

For those unfamiliar with mass spectrometry, in its simplest form it is a technique which is used to determine the identity of sample components based on their mass-to-charge ratio and, in some cases, how the molecule fragments when ionized. MALDI is something of a variation of this technique. In this technique, the sample to be analysed is mixed with a particular matrix material and applied to a plate. A laser irradiates the sample and matrix, causing ablation and desorption, after which the sample is ionized and then accelerated and detected using mass spectrometry.

Researchers have applied MALDI MS to detecting the presence of blood by specifically focusing on the detection of haem and haemoglobin molecules based on their mass-to-charge ratios. These molecules are vital components of blood, with haemoglobin being the protein responsible for oxygen transportation and haem being a compound embedded into haemoglobin which provides the iron essential for oxygen binding. By subjecting known and suspected blood stains and bloodied fingermarks to this technique, haemoglobin chains could be detected even in traces of blood invisible to the naked eye. Initial research into this technique studied human, equine and bovine haemoglobin, establishing that it is possible to determine whether or not haemoglobin was from a human source using mass spectrometry at a high mass range. Both fresh and aged blood samples could be successfully analysed, making the application potentially beneficial to samples from various points in time. Furthermore, the technique has proven to be compatible with other methods often used by investigators when attempting to enhance fingermarks at incident scenes, meaning the new method is not likely to interfere with existing procedures.

A typical haemoglobin molecule.

A typical haemoglobin molecule.

This fascinating application of matrix-assisted laser desorption ionisation mass spectrometry offers a whole new world of possibilities in blood detection in forensic science. Although at present such instrumentation is far from being the norm in the forensic scientist’s arsenal, the applications of advanced mass spectrometry techniques to answering some of the simpler yet vital questions during a criminal investigation make for a captivating read.

References

Bradshaw, R et al. Direct detection of bloos in fingermarks by MALDI MS profiling and imaging. Science and Justice. 45 (2014), pp. 110-117.

King’s College London. An Introduction to Mass Spectrometry Based Proteomic. [online][Accessed 16 Feb 2015] Available: http://www.kcl.ac.uk/innovation/research/corefacilities/smallrf/mspec/cemsw/instr/Mass-Spec-based-Proteomics.pdf