Expert Witness

by Anna Sandiford

  Back to the original question now: why is there any need to employ an independent expert? It comes down to basics: an independent quality control check. When I present lectures on this topic, there are six cases to which I refer. As with New Zealand, England and Wales has its fair share of problems when it comes to forensic science and there are unfortunately several other cases to which I could refer, but those below are the least technical and the most demonstrative. There are of course several high-profile New Zealand cases that could be used as examples but I intend sticking to English cases because people get tied up with the emotional aspects, which cloud the importance of the science. Emotions and science don’t mix so in New Zealand I talk about English cases and, in England, I talk about New Zealand cases.

  Angela Cannings and Sally Clark

  In 1989, Angela Cannings’ baby died at the age of 13 weeks. Another seven-week-old son died in 1991 and in 1999 her 18-week-old son died. After the first death, the view seemed to be that this was unfortunate — poor lady. The subsequent deaths were viewed as some thing else and more than just coincidence — how could a woman have more than one baby die as the result of natural causes? She was charged with murder, tried and convicted.

  Sally Clark gave birth to a boy in 1996 but he was found dead in his Moses basket at 11 weeks of age. Death was certified as ‘natural causes’. She later had another boy in 1997 who, eight weeks later, suddenly collapsed. The parents requested a specialist pathological examination, as did the hospital paediatrician. Unfortunately, this did not occur and the postmortem was performed by the local Home Office pathologist. After four weeks’ delay, the parents were arrested. The pathologist had reported retina and brain damage attributed to ‘baby shaking’. Review of the first child’s death resulted in the original certification of natural causes being replaced with smothering. In July 1998 Sally Clark was charged with the murder of both babies. An expert paediatrician for the prosecution said during the trial that the chance of a double cot death in the Clark family, at one in 73 million, was ‘vanishingly small’. However, it was accepted by both the Crown and the defence that there was no evidence both babies died of cot death. The same expert witness gave evidence in the trial of Angela Cannings. Crown evidence was that Mrs Cannings had smothered her children.

  Figures from the Care of Next Infant (CONI) charity are that one cot death occurs in every 8500 babies, but after one cot death the risk of a second actually increases to one in 200. The statistic of 1:73 million quoted by the expert in the Sally Clark case is five times smaller than the chance of winning the English lottery.

  The Royal Statistical Society issued a statement in 2001 (News Release, Tuesday 23 October 2001), prompted by issues raised by the Sally Clark case, expressing its concern at the misuse of statistics in the courts:

  In the recent highly publicised case of R v Sally Clark, a medical expert witness drew on published studies to obtain a figure for the frequency of sudden infant death syndrome (SIDS) in families having some of the characteristics of the defendant’s family. He went on to square this figure to obtain a value of 1 in 73 million for the frequency of two cases of SIDS in such a family.

  This approach is, in general, statistically invalid. The well-publicised figure of 1 in 73 million … has no statistical basis.

  After many battles, both women had their convictions quashed and were released from prison, Sally Clark in 2003 after three years in prison (she died in 2007, aged 42), and Angela Cannings in 2004, after 20 months in prison. In the review of Angela Cannings’ case, the court was told the paediatrician’s evidence was misleading and, in future, his testimony would need a ‘health warning’ attached to it. A BBC investigation showed that on her father’s side, Mrs Cannings’ grandmother had lost one child to cot death and her great-grandmother had lost two.

  The paediatric expert witness was eventually struck off in 2005 but was later reinstated. The original pathologist in the Clark case was found guilty of serious professional misconduct.

  The Birmingham Six

  The Birmingham Six (never let it be said that the British media is short of catchy tag lines) were six men sentenced to life imprisonment in 1975 after being tried and convicted of the 1974 series of pub bombings in Birmingham, central England. Twenty-one people were killed and 162 were injured in the two coordinated bomb blasts, which were separated by two minutes.

  A prosecution forensic scientist used a positive result from a screening test to claim a 99 per cent certainty that two of the defendants had handled explosives. The test results were opposed by a prominent defence expert. The test used is not conclusive and, over time, proved to have limited value; the test has not been used by the British police forces since the mid-1980s.

  The case was far more complicated than this brief summary, but the convictions were declared unsafe and overturned in 1991 by the Court of Appeal. At the appeal, evidence was presented regarding fabrication and suppression of evidence by the police and the forensic evidence was discredited. This led to the Crown withdrawing most of its case against the men. The Court of Appeal stated that the conclusion of the forensic scientist ‘… was wrong, and demonstrably wrong, judged even by the state of forensic science in 1974’.

  Damilola Taylor

  Damilola Taylor was a 10-year-old boy who died in November 2000 as the result of a single stab wound to his left leg, while on his way home from a library in South London. Numerous items were seized from several suspects by the police and examined by a major forensic science laboratory. Several youths were arrested; four were charged with Damilola Taylor’s murder. While they were subsequently cleared in April 2002, after their acquittals the police reinvestigated the case and sent all items seized to a different forensic science laboratory. Scientists at the second laboratory found traces of Damilola’s blood on a training shoe worn by one of the arrested youths and on the cuff of a jumper belonging to another. Fibres within the stain found on the training shoe were indistinguishable from those in Damilola’s trousers. The first examination of the shoe had been undertaken by an Assistant Scientific Officer (ASO). The ASO’s work had been reviewed by the scientist who eventually reported the case, but the reporting scientist didn’t actually examine the shoe themselves, apparently because of a lack of time. As a result of this case, forensic organisations tightened up their examination and review procedures. Reporting officers must now examine the items themselves, although this is done after the main examination has been done by an ASO. While police eventually achieved manslaughter convictions in 2006 for two youths, who were aged 12 and 13 at the time of Damilola’s death, there was significant criticism not only of the way the forensic science was handled but also of the way the case was investigated by the police.

  Omagh bombing

  In August 1988, a paramilitary car bomb went off in Omagh, County Tyrone, Northern Ireland. Twenty-nine people died and approximately 220 people were injured. The attack was carried out by the Real Irish Republican Army (RIRA), who later claimed responsibility.

  The person most recently charged with the attack was Sean Hoey. A significant part of the Crown case relied upon the results of low copy number (LCN) DNA analysis linking Mr Hoey with several bombs. However, during the trial an alleged leading authority on LCN DNA indicated that the technique wasn’t up to muster and in late 2007 the case against Mr Hoey collapsed.

  As a result, the Crown Prosecution Service (CPS) in England and Wales briefly suspended the use of the technique in early 2008 and all cases going through the courts in which LCN DNA findings formed part of the case were reviewed. Although the CPS never said how many cases were involved, the Forensic Science Service had used LCN DNA findings approximately 21,000 times, although not all led to a prosecution.

  The Home Office Forensic Regulator was to review how LCN findings were used and what should happen with the technique in the future. Although some scientists are unhappy with the method, many say that as long as the technique is applied correctly, all appropriate precauti
ons are taken and the individual circumstances of cases are considered, then the findings are reliable.

  The method may not produce an exact match with a person’s DNA, which is why careful interpretation of the results using appropriate databases and software is so crucial. The technique is only used in two other countries for evidential purposes in criminal cases: the Netherlands and New Zealand.

  Julie Ward

  Julie Ward was a British photographer, whose burned and dismembered body was discovered in 1988, in the Masai Mara Game Reserve, in Kenya. The official story was that she had been mauled to death by lions and her body was then struck by lightning.

  Her father refused to accept this version of events and pursued an independent investigation. This investigation uncovered, among other things, that the coroner’s report had been altered to cover the fact that Julie’s bones had been cut with a sharp instrument rather than gnawed by animal teeth.

  In 2008, Mr Ward was hopeful that DNA evidence would be of assistance in bringing to justice those who were responsible for his daughter’s murder. It’s now two years on and the Metropolitan police are still working with Kenyan authorities in an effort to solve the case.

  All of the examples I’ve outlined above demonstrate why it is crucial not to accept every thing presented in evidence at face value — challenge the assumptions at every turn. If there’s a failing in the system, let’s look at it, fix it, improve and move on.

  Before we talk about what makes an expert an expert, let’s linger briefly over one who is clearly anything but. Several cases of shonky forensic science spring to mind but, for me, the one that could make a Hollywood film is that of a truly bogus ‘forensic scientist’ from Manchester, England. This man had been passing himself off as a forensic investigator for 26 years. He worked on more than 700 cases, all of which will need to be assessed in case his testimony resulted in any miscarriages of justice. During that time, he fleeced the tax payer of at least £250,000 in payments. He is reported to have cut and pasted some of his reports from the Internet and even had a special fluorescent jacket made for him with FORENSIC INVESTIGATOR on the back.

  He’d bought his qualifications (BSc in Forensic Science, a Masters with excellence in Forensic Investigation and a Doctorate in Criminology) from a sham university because, as he told the court, it ‘looked easier’ than going to a real university. To be fair, he’s not wrong — training for anything is tough work but it doesn’t mean we should all go around cheating, does it?

  He was charged with many and varied things, including obtaining a money transfer by deception, obtaining property by deception, perverting the course of justice and perjury. The judge at his trial referred to him as an ‘inveterate and compulsive liar’.

  He was originally jailed for five years but I read recently that he was also charged and eventually convicted in December 2009 of sexual assault offences and is serving an indefinite term. Not really a poster boy for forensic scientists.

  There’s been an awful lot of brouhaha over the years about what makes an individual an expert in a given area. Many cases, unfortunately, can be used as examples to demonstrate what happens when forensic science goes bad. The lack of attention in the Damilola Taylor case is one, even though the scientists weren’t deliberately trying to make a muck-up. The Birmingham Six case was a key factor in change within the police and one of the biggest shake-ups in British policing came with the introduction of the Police and Criminal Evidence Act 1984, now more commonly referred to as PACE. The job of PACE is to ‘strike the right balance between the powers of the police and the rights and freedoms of the public’ because they got in the doo-doo for beating confessions out of people, among other things. PACE is now constantly being updated (details are available on the Internet) because the government and the police recognise that modern policing changes as the population and the population-related problems change.

  Forensic science in England and Wales had changed for the better as well and all was looking pretty good, but despite a tightening of controls and procedures within the forensic science agencies, more trouble was to come. The CSI effect led to literally hundreds of courses with the word ‘forensic’ in the title. A 2004 Home Office Science and Technology Select Committee identified that there was a ‘poor standard of higher education forensic science provision’; the Forensic Science Occupational Committee of Skills for Justice stated that ‘forensic science learning provision … was not sufficiently preparing learners for employment in forensic science’.

  New Zealand has the right idea I think — you can’t study forensic science here at under graduate level; you have to have at least a first degree in some thing scientific. Excellent idea. Otherwise, you end up with graduates with degrees that aren’t useful for anything. At least with a full science degree a graduate has other options if forensic science doesn’t work out. Plus they are given a full grounding in a decent science.

  The good old US of A has had massive problems with the standards of its forensic science and they’ve also been undertaking a review. Some particularly awful cases have stoked the fires of reform in a substantial way, such as the case of Cameron Todd Willingham, who was convicted of killing his children in a house fire he allegedly set. Mr Willingham was executed in February 2004, still maintaining his innocence. A review of the case has since found that the forensic science used to convict him was inadequate. More action will probably occur on this matter, which seems to be only the tip of the iceberg of much needed reform.

  In 2009, the USA National Research Council Committee on Identifying the Needs of the Forensic Sciences Community published a report entitled, Strengthening Forensic Science in the United States: A Path Forward.

  The report says:

  Because accused parties in criminal cases are convicted on the basis of testimony from forensic science experts, much depends upon whether the evidence offered is reliable. Furthermore, in addition to protecting innocent persons from being convicted of crimes that they did not commit, we are also seeking to protect society from persons who have committed criminal acts. Law enforcement officials and the members of society they serve need to be assured that forensic techniques are reliable. Therefore, we must limit the risk of having the reliability of certain forensic science methodologies judicially certified before the techniques have been properly studied and their accuracy verified by the forensic science community.

  Basically, this is the States saying that they don’t want any more shonky forensic science, thanks very much, and we’re going to do some thing about it, so shape up.

  Overall, the report basically stated that the accuracy and reliability of practically all forensic science methods, ranging from glass to finger prints, had not been established adequately through rigorous scientific scrutiny. The American Academy of Forensic Sciences (AAFS) annual conference in 2010 was tellingly entitled, Putting Our Forensic House in Order: Determining Validation and Expelling Incompetence.

  So, not only is forensic science in the States being shaken upside down until the grotty bits drop out of its pockets, someone somewhere is getting paid to do the work that should have been done long ago, on an ongoing basis. Let’s hope one of the resolutions that arises from the AAFS meeting is that forensic science techniques should be reviewed thoroughly now and regularly as time progresses. The situation is that if fundamental problems are found with a particular technique or evidence type, then convictions might be called into question, which could throw the whole system into disorder, incurring enormous expense and all the obvious associated problems.

  To my mind, that’s not a good enough reason not to do it. If people are sent to prison based, even in part, on scientific findings, then the science must be robust and reliable. If science is reviewed regularly and the law takes that into account then it should be possible to work out a system whereby the courts can be sure that the science is up-to-date, which in turn adds to the strength of science in court. It also might prevent the current stink that’s going o
n in Texas over the inadequate forensic science presented in Cameron Todd Willingham’s case.

  In order to address the issues about forensic science in the States, academics at UCLA are being granted funds to consider error rates in latent finger print evidence. As I mentioned earlier, some would ask whether or not this sort of exercise should have been completed long ago. As with any other area of applied science, regular review should be undertaken. Unfortunately, this is not some thing that necessarily occurs in forensic science, partly because some agencies aren’t keen on their databases being examined. I never had any problem reviewing glass or footwear mark databases when I was in England but who has ever fully analysed the data in national DNA databases?

  Courtesy of the news media and programmes like CSI, we all know that DNA can be an extremely powerful tool in crime solution. When a sample from a crime scene is compared with a sample from an individual it should be the easiest thing to be able to say whether or not they originated from one and the same person, shouldn’t it? In forensic science (and many other areas of science), without a solid and reliable database, interpretation of results can be troublesome or even meaningless. Once results have been obtained, a decision has to be made about how to report the findings so that the maximum amount of information can be gained from them. The way that’s done varies between evidence types.

  In cases involving physical fits, it can often be a simple case of yes, the pieces fitted together or no they didn’t — conclusive either way, no grey areas. For other areas of forensic science it’s a bit more complicated. DNA, for example, has a complex interpretation method based on statistical interpretation, which is part of the reason why DNA reporting in Victoria, Australia, was suspended at the latter end of 2009, temporarily halting the use of DNA in criminal cases because of a problem with interpretation of results after new technology was brought online in September. As a result of the new technology, more detailed information was obtained from DNA samples but the statistical models used to interpret the data were inadequate. In simple terms, it meant the DNA profiles could result in the wrong people being arrested, tried and convicted — miscarriage of justice, everyone’s worst nightmare.