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By Helen Gavaghan
"...the ultimate responsibility must rest upon the judge or judges to ensure the expert is asked the right questions, that the evidence is fairly presented, and the accused is given a proper opportunity to challenge it, and the decision on the evidence is logically explicable."
The Rt Hon Lord Thomas of Cwmgiedd, Lord Chief Justice of England and Wales
From "The Legal Framework for more robust forensic science evidence."
On 22nd JUNE, 2015 Britain's national academy of science, The Royal Society, published an issue of Philosophical Transactions B devoted to forensic science - the science related to solving and prosecuting crime.
Among the articles is one by Lord Thomas of Cwmgiedd (1), the Lord Chief Justice of England and Wales, laying out the scientists' responsibilities when undertaking the task of expert witness.
Evidence must have a reliable scientific basis;
The scientist testifying must be reliable;
All understand properly the ambit of the expert's opinion;
Safeguarding the chain of evidence;
Explain the evidence to judge and jury such that they can properly understand it.
On the question of ambit, on 21st May, 2014 the UK Supreme Court handed down a judgment in which the jurists made clear that experts must never act or appear to act as advocates. See  UKSC 30. On appeal from:  CSIH 68, reported on www.gavaghancommunications.com at http://www.gavaghancommunications.com/supremecourt.html
In his article Lord Thomas made reference to The Law Commission's recommendations on forensic evidence, drawn up in response to the House of Commons Science and Technology Select Committee's call for reform in relationship to expert evidence. The Law Commission wants a tightening by Courts on criteria for admissibility of expert evidence, and Lord Thomas agrees with them.
Lord Thomas then writes:
"Even if we have absolute confidence in the reliability of the science and the expertise and integrity of expert witnesses, we have to ensure that we continue to be able to use juries for trials where forensic evidence, even complex forensic evidence, plays a central role in the trial. This task will become even more acute as technology pushes the boundaries and we are able to do things in new and novel ways."
Procedural rules, Lord Thomas says, exist which enable points of difference between experts to be isolated from the areas of agreement between them. However, there is also an element of chance in whether a matter of scientific evidence comes to judicial attention. And Lord Thomas made reference to fingerprint evidence contested in 2011. The first such evidence challenged in England and Wales, writes Lord Thomas, for "many, many years".
The field of fingerprint analysis is ripe for statistical modelling research, writes Christophe Champod, from the School of Criminal Justice at the University of Lausanne in Switzerland (2).
Making reference to US practise, professor Champod writes that fingerprints are used to determine among identification, exclusion or inconclusion; and that contextual bias has been noted among fingerprint experts. He says that the reliability of fingerprint evaluation methods is unknown, but by contrast experts testify in a language of absolute certainty.
For the future Christophe Champod does not envisage machines replacing people in the examination of forensic fingerprint evidence, but he does think the field is going to have to use statistical models and probabilistic measures if it is to reliably report what the evidence is actually saying.
Yet in an article on biometrics Anil Jain and Arun Ross from Michigan State University write of automation of fingerprint analysis as inevitable (3). Drs Jain and Ross , from the department of computer science and engineering, define biometrics as the automated recognition of individuals based on their behavioural and biological characteristics. Homeland security and fraud prevention are the twin drivers of the field, they say. Tattoos were used to identify victims of 9/11, and law enforcement agencies in the US routinely photograph and catalogues tattoos of suspects.
Though DNA analysis is a different problem in nature and complexity from fingerprint comparisons, and though the plausible maximum sample size is larger, DNA has set a precedent of presenting statistical forensic evidence which fingerprint experts might follow.
In his article (4), John Butler from the National Institute of Standards and Technology in Gaithersburg, US, writes that DNA protocols can "expect to become more rapid and sensitive and provide stronger investigative potential". He notes that new genetic markers for human identification have been identified, but that the usual challenges of sample quality remain.
Pathology, like fingerprinting and DNA analysis is, in the field of forensics, caught at a crossroads. Techniques such as computerised tomography, magnetic resonance imagining and post mortem angiography of vasculature, could transform forensic science. Such a revolution in forensic medicine started in Switzerland in the late 1990s, writes Stephan Bolliger and Michael Thali, from the department for forensic medicine and imaging at the University of Zurich (5).
Though paradigm shift is a term appearing through much of the published material in this special issue on forensic science that is not what the articles are about; neither in law or science. Instead the authors reprise state of the art, note that techniques standard in disciplines other than forensics could be brought into the field, list problems to be solved, point out perceived weaknesses in the system, and highlight interesting history factoids, such as the first use by Argentinian police in 1891 of fingerprinting for identification.
Topics covered include: biometrics, assessment of forensic science in Court, new psychoactive substances, technology in modern forensics, imaging and autopsies, so-called virtual autopsy, future of DNA analysis, cognitive neuroscience, legal framework for forensic science, fingerprint identification, trace evidence, integrating research into practise, logical foundation and forensic science, and odour in forensic science,
1. Rt. Hon. Lord Thomas of Cwmgiedd (2015). "The legal framework for more robust forensic science evidence." Phil. Trans. R. Soc. B 370. http://dx.doi.org/10.1098/rstb.2014.0258
2. Champod C. (2015). "Fingerprint identification: advances since the 2009 National Research Council report." Phil. Trans. R. Soc. B 370. http://dx.doi.org/10.1098/rstb.2014.0259
3. Butler J. (2015). "The future of forensic DNA analysis." Phil. Trans. R. Soc. B 370. http://dx.doi.org/10.1098/rstb.2014.0252
4. Jain A.K., Ross A. (2015). "Bridging the gap: from biometrics to forensics", Phil. Trans. R. Soc. B 370. http://dx.doi.org/10.1098/rstb.2014.0254
5. Bolliger, S.A.; Thali M.J. (2015). "Imaging and virtual autopsy: looking back and forward." Phil. Trans. R. Soc. B 370. http://dx.doi.org/10.1098/rstb.2014.0253