Forensics

by Val McDermid

  In the Stephen Lawrence case, hard work from the prosecution revealed evidence that led to the conviction of two vicious racist murderers. Evidence that ‘would not fill a teaspoon’ sank Gary Dobson, with CCTV footage helping him on his way down. But evidence can be a double-edged sword, and sometimes the lawyers can find ways to use it that don’t serve justice well.

  Jurors love CCTV because, while a lot of evidence used in trials can be argued one way or the other, video evidence provides a clear and irrefutable picture of what happened. But this impartiality means it records everything that happened, not just what the prosecution would like to see. In his 2010 book Defending the Guilty, criminal lawyer Alex McBride describes a case in which he got someone off through extraordinary use of CCTV evidence. ‘Giles’ had been caught on a high-definition CCTV camera punching a man in the face. He was stripped down to his waist, and anyone could read his lips in the seconds after the punch: ‘Do you fucking want some more?’

  As McBride watched the footage to prepare his defence, his heart sank. Despondently he watched to the end of the tape, until it went black. Then suddenly it flickered into life again. McBride watched in astonishment as a police officer pinned Giles’s co-defendant, ‘Dave’, up against a wall, picked him up by his shirt and slammed him to the floor. When Dave’s girlfriend tried to intervene, the officer slammed her down, too. She tried to get up, but the officer kept her down with his boot.

  McBride showed the clip to Dave’s defence lawyer and together they came up with a plan, to demand that all charges against their clients be dropped in return for their not pressing charges against the police for wrongful arrest and assualt. To their delight, the prosecution agreed and Dave and Giles went free. To get his client off, McBride had used an outtake from an otherwise crystal clear moving picture of guilt. ‘The golden rule of defence,’ he writes, ‘is that the less evidence there is, the better – unless it is evidence that contradicts what the prosecution witnesses are claiming under oath.’

  The Crown Prosecution Service is an organ of state. Its links with the police give it a head start on the defence, but it must share all its findings with the other side before a trial. The principle of sharing evidence has to do with the legal concept of ‘equality of arms’, whereby similar resources must be available to the prosecution and the defence. Without equality of arms a fair trial is impossible.

  Equality of arms means that, in theory, both the prosecution and the defendant should have access to their own expert witness to give a view on what the evidence means. However, judges are increasingly encouraging prosecution and defence experts to get together once they have analysed the evidence, to discuss their findings in pre-trial meetings. This has implications for equality of arms, because it saves time and money, both of which are, given the recent cuts to UK legal aid, in ever shorter supply. The money saved can then be used to pay for other experts. But it is about more than just equality of arms, as one forensic psychologist explains: ‘I submit a report, the other side submit a report. If there is a lot of difference we get together with some coffee, hammer out our differences and come to some positive results. It saves both of us going into court for three days and boring the pants off juries who have no idea about the different theories.’

  Forensic anthropologist Sue Black agrees. ‘It’s important to meet beforehand and iron out where the agreements and disagreements are. It helps to remove a lot of the posturing that goes on in the courtroom.’ In a recent case in which Sue acted as a defence expert without a pre-trial meeting, it turned into a ‘train wreck for the prosecution experts from beginning to end’. At one point the judge asked if the experts from both sides could get together to talk. But the defence and prosecution lawyers both thought there was so little common ground that there would be no point to them meeting. The prosecution’s case collapsed and folded, which ‘did no one any good at all’.

  Experts don’t always have to testify in person: whether it’s written by one or two experts, a paper report is often enough for the court. Blood expert Val Tomlinson ‘deal[s] with far more cases than I’d ever dream of going to court with … I actually stand in the witness box maybe two or three times a year.’ The experience of going on the stand brings up all sorts of emotions – excitement, pride, satisfaction, fear, irritation, humiliation. The mixture depends on the nature of the case – and the personality of the expert themselves.

  The very best laboratory scientist may not be able to show the self-control and confidence to perform well in the witness box. Pathologist Dick Shepherd says, ‘Lots of scientists can find evidence but there is a unique skill to standing up in court and giving that evidence in a way that a jury with no previous knowledge can understand.’ It’s a point often made that court proceedings are a kind of theatre – and, as such, good performers, like the famously charismatic pathologist Bernard Spilsbury, often make the best impressions on juries.

  While experts are only allowed to answer the questions that lawyers ask them, they are at the same time encouraged to give their opinion. It is their job to find and interpret facts, not to parrot known ones. Of course, the distinction between fact and opinion is a tricky one, and there is a heavy responsibility on the expert witness to say nothing that might mislead the jury. If an expert testifies that a badly smudged fingerprint belongs to Joe Bloggs, is that a fact or an opinion? Or if a blood spatter expert says that the pattern of blood droplets means the victim must have been lying on the ground when the fatal blow was struck, how can a jury assess that evidence?

  Furthermore, by its nature, science is provisional: theories are open to rejection or modification in the light of new evidence. Fiona Raitt says, ‘Much expert testimony goes to the core of scientific development, which is in a constant state of discovery and refinement. What we know today is sometimes very different from what we knew yesterday.’

  Expert testimony is defined as that which is outside the general knowledge of an average member of the public. No matter how strongly they feel about it, the expert witness must leave ‘the ultimate question’ of guilt or innocence to the jury. To an extent this is a matter of semantics. While Val Tomlinson (see p.155) couldn’t say, ‘The DNA evidence proves that the Reed brothers did it,’ she could (and did) say, ‘It is my opinion that the most likely explanation for the DNA results obtained is that the knives were brought to the victim’s home by Terence Reed and David Reed respectively, and that they were handling these knives at the time at which the handles broke.’

  The principle of ‘knowledge beyond the general’ was cemented in 1975, after the trial of Terence Turner. Turner was sitting in his car with his girlfriend Wendy, who he thought was carrying his baby. But they argued and, in the heat of anger, she told him that she’d been sleeping with other men while he’d been in prison. One of them had made her pregnant, not him. Boiling over with rage, Turner seized a hammer that was by the driver’s seat and smashed Wendy fifteen times across the head and face. He then got out of the car and walked to a nearby farmhouse, where he told someone he had just killed his girlfriend. In court, he said he didn’t know what he had been doing, his hand just fell on the hammer and ‘it was never in my mind to do her any harm’.

  Turner’s defence was provocation. If the jury had gone with it, its verdict would have been manslaughter. Instead it found him guilty of murder. He appealed against the verdict on the grounds that the judge had not allowed the jury to hear the report of a psychiatrist. The psychiatrist had written that Turner had no mental illness but was very sensitive to the feelings of others. His ‘personality structure’ made him vulnerable to anger. And his anger was understandable because of his relationship with the victim. If her confession had taken him by surprise, he could have killed her in ‘an explosive release of blind rage’.

  His lawyer argued that, if the jurors had been allowed to hear the report, they would have been better able to understand Turner’s actions. Lord Justice Lawton reminded the Court of Appeal, ‘Jurors do not need psychiatrist
s to tell them how ordinary folk who are not suffering from any mental illness are likely to react to the stresses and strains of life.’ If psychiatrists and psychologists could be called in all cases to prove the probability that the accused was telling the truth, he said, ‘Trial by psychiatrist would be likely to take the place of trial by jury.’ Turner’s appeal was rejected. Fiona Raitt explains: ‘The expert has to demonstrate that their field is deserving of the label “expertise” – handwriting is clearly one, so is knowledge of what explosives do – but when it comes to human behaviour, that’s the one the judges always splutter at.’

  In the vast majority of cases, forensic scientists give the jury important information to consider and help them to understand it. It’s the trials that go wrong that give judges and academics like Fiona most to ponder. They are painful for all concerned, but they also pave the way for better justice to be delivered in the next similar trial. Experts with shelf-loads of published work and a Scrabble board of acronyms at the end of their names have the biggest burden of expectation in court. On the whole juries will give their opinion extra weight, especially when they have charisma on their side, too.

  A recent example is Roy Meadow, a paediatrician famous for classifying Münchausen Syndrome by Proxy, whereby parents harm their children in order to get the attention of doctors. But in Britain, Meadow’s name is best known in relation to Sudden Infant Death Syndrome, or ‘cot death’, in which an apparently healthy baby dies with no obvious medical cause. According to Meadow, ‘One sudden infant death is a tragedy, two is suspicious, and three is murder until proven otherwise.’ British social workers and child protection agencies took ‘Meadow’s Law’ straight to heart, with catastrophic results for a number of families.

  In 1996, an 11-week-old baby boy died suddenly in his Moses basket at home in Cheshire. Two years later, his brother Harry died in similar circumstances at the age of only eight weeks. Pathologists found signs of trauma on the babies’ bodies. Their mother, Sally Clark, the daughter of a policeman, was arrested and charged with two counts of murder.

  Sally stood trial in November 1999. Several paediatricians testified that the babies had probably died from natural causes, believing that the trauma on their bodies had come from attempts to resuscitate them. But the prosecution lawyer portrayed Sally as a ‘lonely drunk’ who missed her well-paid job as a solicitor and resented her children for keeping her at home. His experts, including Sir Roy Meadow, first thought the babies had been shaken to death, although some later decided they had been smothered. Meadow put the odds against two cot deaths occurring in one affluent household at 73 million to one. He used an analogy to ram the message home: ‘It’s like backing an 80–1 outsider in the Grand National four years running, and winning each time.’ On the back of these very damning stats from a newly knighted doctor, the jury found Sally Clark guilty of murder, by a majority of ten to two.

  Sally appealed against her conviction, after the Royal Statistical Society called Meadow’s 73 million to one a ‘serious statistical error’. To get his figure Meadow had simply squared the 8,500 to one ratio of live births to cot deaths in affluent non-smoking families. This failed to take into account the fact that a sibling of a cot death baby shares very similar genetics and environment, and is therefore at far greater risk than the rest of the population of cot death themselves. The Foundation for the Study of Infant Deaths stated that in the UK second cot deaths in the same family actually occur ‘roughly once a year’. But, in October 2000, Sally’s appeal was dismissed when the judges claimed that Meadow’s figures were a ‘sideshow’ that would not have affected the jury’s decision.

  Then, new evidence from Macclesfield Hospital came to light showing that another expert witness at the trial, pathologist Alan Williams, had failed to disclose the results of tests he had done on blood samples. These suggested that one of the babies had died from the bacterial infection Staphylococcus aureus, not from being shaken or smothered. Sally appealed again. This time, in January 2003, her conviction was quashed and she was freed. The appeal court judges commented that, while Meadow had got his stats grossly wrong, it was the findings from Macclesfield Hospital – produced by a lawyer who had worked for free – that had made them overturn the conviction. They lambasted as ‘completely out of line’ Alan Williams’ explanation of why he had discounted the blood test result: because they were inconsistent with his belief that the baby boy had not died from natural causes.

  Sally’s release prompted a review of shaken baby cases. Two other women, Donna Anthony and Angela Cannings, had their murder convictions overturned and were released from prison. Three of Cannings’ babies had died before reaching twenty weeks. She had appealed when it was discovered that her paternal grandmother had had two cot death babies, and her paternal great-grandmother had lost a baby, too. Trupti Patel, who was also accused of murdering her three children, was acquitted in June 2003. In each case, Sir Roy Meadow had testified about the unlikelihood of multiple cot deaths in a single family. ‘In general,’ he had said, ‘sudden and unexpected death does not run in families.’

  Roy Meadow and Alan Williams were subsequently struck off the register of the General Medical Council for ‘serious professional misconduct’. In 2006, Meadow won his appeal to be reinstated, on the grounds that he had made his statistical mistake in good faith. But, unlike Bernard Spilsbury, his reputation had been tarnished within his own lifetime. In 2009, Meadow himself applied to be removed from the GMC register, meaning he can no longer work as a doctor in the UK or testify as an expert witness. British courts no longer prosecute parents of babies suffering cot deaths on the evidence of a single expert witness.

  Roy Meadow arrives at the General Medical Council to face a professional conduct committee over evidence he gave in several baby death cases

  Sally Clark never recovered from her ordeal. Not only had she lost her two tiny sons, but she had been portrayed in the media as a child killer, and then spent three years in prison being treated by other inmates as the epitome of evil. She died in 2007 from alcohol poisoning, at the age of forty-two, leaving her third son without a mother.

  Scientists like to give their theories a good airing. Using them successfully in a criminal case improves their standing in the academic community. Sue Black has learned to be wary of this. ‘I’ve been a witness for the court where both sides have agreed that whatever it is that I come out with they will go with it. I’m not saying that that’s good, because in certain circumstances, depending upon your expert witness, it could be dangerous.’ Pondering over the kinds of subtle errors that are sometimes made, Fiona Raitt wonders ‘to what extent some experts can be bought? You’d like to think not but it is a very unpleasant world.’

  Sally Clark outside the High Court after her release

  There are clearly dangers in accepting what an expert says at face value. But there is also a danger that the court can go too far the other way and dismiss all cutting-edge science as newfangled and unreliable. In the ideal scenario, judges and lawyers put pioneering scientists under pressure in the witness box, testing the limitations of a technique and giving them new directions to explore back in the lab. When Sue Black first tried to identify a child abuser by the pattern of the veins on his hand, the accused man’s lawyer lambasted her for using an unprecedented technique. Anxious that her use of the technique had been a contributing factor in the defendant’s acquittal, Sue knew that she still needed to flesh out her vein pattern analysis with more data (see p.185). Ultimately, the technique was used to convict a paedophile who had filmed his abuse of young girls.

  This is a good example of how cross-examination can strengthen forensic techniques, by putting pressure on them. If the evidence is sound, the theory goes, jurors will find it all the sounder once they’ve seen it flexed. But it doesn’t always work like that. In fact, people have been questioning the truth-seeking value of the trial system for a very long time. Shortly before his death in 1592, the French lawyer and philosopher Mi
chel de Montaigne wrote, ‘First we feel enmity for the arguments and then for the men … The result of each side’s refuting the other is that the fruit of our debates is the destruction and annihilation of truth.’ In other words, when lawyers fail in their efforts to attack the evidence, they turn on the person who’s giving it instead. One forensic scientist I talked to positively relishes it. ‘I love the challenge of being cross-examined by barristers – in the beginning it was, “Young man, in your limited experience …” Nowadays I often have great fun with barristers because of the gamesmanship.’ Robert Forrest is stoical about it: ‘If you don’t like the heat, you should get out of the kitchen.’

  Criminal lawyer Leo Seelig believes it would be ‘a great shame’ if experts did not have to face the heat of cross-examination: ‘To throw into doubt the qualifications of an expert witness is a perfectly reasonable line of enquiry. But it’s risky, because it can be unpleasant for the jury and, if you lose them, you’ve lost the case. The advice given to advocates is not to take on experts at their own game but to put them in the position where, by their own analysis, they can’t be sure. And experts do make mistakes all the time. Little things in their reports can be blown up out of proportion. That simply does work, I’m afraid. Which is why experts have to be doubly careful with every detail of their reports.’