Expert Witness

  The glass work in this case was quite complicated, so I’m not going to précis it. Take it from me that the critical issues were not only the number of glass fragments recovered from each individual but the physical and chemical properties of those glass fragments, as well as the order of events. Mr Smith was eventually found guilty of burglary and manslaughter.

  Moving on from case examples to modern policing of crimes involving glass, police in England have developed a ‘crime scene kit’ to give to bar and pub owners to collect glass samples after drunken brawls. Glassings or bottlings, when a glass or bottle is smashed before being thrust into the victim, often in the face, are a common occurrence in British society, usually after 10 pints of lager and shortly before a kebab on a Saturday night.

  The biggest problem with cases of this type is that witnesses are often drunk and can’t really remember what happened, the CCTV footage isn’t always clear and the glass used in the event is usually crushed and then swept up because, obviously, it’s dangerous. In cases where broken glass is successfully recovered, the scientific results can be very good — fingerprints can demonstrate the manner in which a bottle was held (bearing in mind that the neck of the bottle is often the strongest part), DNA from blood can show whose body said weapon was used against but, too often, this type of information is lost in the aftermath.

  Police in Plymouth, Devon, have decided to try to combat the problem of lost evidence by handing out clean dustpan and brush kits to local pub and bar owners so they can collect the ‘evidence’ for later examination.

  To me, this could go one way or the other. On the one hand, it’s good because the collection of this sort of information could potentially increase the number of successful convictions in what is a horrendous and often life-altering event for the victim: in the short term, blood transfusions are often required for victims in order to replace lost blood; longer term, severe scarring is not uncommon. On the other hand, if these dustpan and brush kits are used by bar and pub owners, the chain of custody doesn’t start with law enforcement personnel — it’s an open book for criticism by the defence regarding the manner in which the glass was collected before it reached the hands of the police. A bar manager could choose to ‘fit someone up’ because, let’s face it, the chances are that they know the troublemakers. I think only time will tell with this one but I’d be interested to be involved with cases of this type as an independent expert, just to see how the prosecution laboratories and the police handle the evidence collection side of things.

  During my time in England I had the dubious pleasure of being involved with many cases relating to drug traces on bank notes. Unlike those of us living in countries with polymer money, such as New Zealand or Australia, those who live in countries with paper money are carrying around bank notes practically all of which bear minute traces of cocaine. At my last look at the database of English bank notes that had been tested for drug traces, 70 per cent of them bore traces of MDMA (Ecstasy), five per cent bore traces of diamorphine (heroin) and five per cent bore traces of THC (found in cannabis). More than 99 per cent of them bore traces of cocaine. This doesn’t necessarily mean that cocaine is the drug most widely used in England and Wales. It just means that, for some reason, traces of cocaine tend to be retained on bank notes more readily than other drugs. The exact mechanism for this is not fully understood but various tests have been undertaken and the bank notes themselves have been examined in various ways, including scanning electron microscopy in order to visualise the structure of bank note surfaces. And the reason analysis of individual bank notes is undertaken? Quite frankly, because they can. I should also add here that it’s not just banknotes that are examined. Swabs are also routinely collected from vehicles, mobile phones, clothes and the surfaces of bags containing bank notes. Basically, anything that can be swabbed can and is examined for the presence of drug traces.

  Banknotes are seized in a variety of cases including criminal cases, Customs and Excise and under the Proceeds of Crime Act. Before this technology came along, in drug-related cases, particularly dealing and trafficking, large quantities of bank-notes were either swabbed en masse or were vacuumed in order to collect any drug traces present. The current method means bank notes can be analysed one by one, which means that if one bank note is very contaminated, it can be picked out.

  There are now answers to some previously difficult questions, such as how do you know it wasn’t just one heavily contaminated bank note that contaminated all the rest? Or, the outer bank notes were handled by Drug Squad officers so they must have contaminated them and that’s what’s caused the results. Some nice people at the laboratory will analyse a selection of individual bank notes in a non-destructive manner. Some times, those nice people at the laboratory will travel to court to give evidence about what they found. Some times, someone like me might go along as well to add comment for the defence. It’s been a hard-fought battle to get this method of analysis accepted in court, partly because people like me flogged away at the inadequacies until it reached the stage it’s at now. I personally have no problem with the methods, analysis or even the interpretation — as long as it relates only to English sterling bank notes; to my knowledge, there is no adequate database for interpretation of other currencies (except perhaps euros). In my humble opinion, very careful consideration should also be given to databases regarding drug traces in vehicles, on mobile phones and many other items.

  In order to be able to under stand the sensitivity of the technique that detects tiny drug traces on items like mobile phones, money, clothing and cars, we need to under stand the size of the particles that can be detected. The method can detect nanogram weights of drugs. That’s 10 to the minus 9 or 0.000000001 gram. To try to under stand the size of this, if a single grain of salt were taken and divided into a thousand parts and each of these individual parts were then subdivided again into a thousand parts, one of those final parts would represent the approximate level of sensitivity of the analytical device. Alternatively, if the total amount of drug traces present on one million sterling bank notes (each contaminated at nanograms levels) were bulked together it would amount in size to no more than a single grain of salt. The quantities of drugs potentially detected by this technique are such that the drugs would not be visible with the naked eye.

  You have to be careful with this kind of scientific information, though, because it sounds extremely impressive. It’s like DNA — once a DNA result has been presented in court, it is extremely hard to cast any measure of doubt on the result, even if it were fundamentally flawed in a given case; it’s just a function of the automatic weight that triers of fact place on DNA findings. It’s similar with drug traces on items; people are fascinated to hear about the prevalence of these drug traces and it creates an automatic acceptance of the results. In more than one case, though, the defendant’s money was found to be contaminated with one drug but he was charged with supply of a different drug altogether. In one case, the problem the police had was that despite a small amount of cannabis found on the defendant at the time of his arrest, there was no bulk quantity of any other drug recovered. He admitted to being a cannabis user but denied supply. The police prosecuted him because high levels of drug traces were found on his money but no one on the Crown’s team looked to see that the charge related to cannabis while the money suggested heroin. Who knows where the money came from, but even the police didn’t think he was a heroin dealer. The case was chucked out of court. Lesson from this case: take a good look at your whole case, including the scientific results, before bringing charges.

  This next story is about drug traces on bank notes and also about court attendance, this time where I was involved as a defence expert for a case in Scotland. I only went because my boss was on holiday somewhere exotic and he couldn’t make it, so I had to go. After getting stuck on the M1 on the way to Luton airport (pouring rain, stationary traffic for an hour) I missed my flight to Aberdeen and had to get on the next flight, which was to Edinb
urgh. Happily, the barrister was in Edinburgh so he picked me up at the airport and we drove to Aberdeen. I have no idea exactly how long it took, except it seemed a very long time in a car with someone I had never met. In fact, I had never even spoken to him before. This is the sort of thing your mother warns you not to do.

  I spent four days in Scotland. It snowed and there was no heating in the hotel, even though Rod Stewart was apparently a co-owner. All I can say is that despite being born in England he’s truly Scottish with iron for blood and thicker vests than I’ve ever owned. I had no thermals with me. There was porridge for breakfast, though, which was good, as it meant no other meals were necessary for the rest of the day. It arrived in an enormous bath-sized bowl, three inches deep and accompanied with either salt or nowt. I didn’t dare ask for honey in case they muttered about me being a southern Sassenach wuss, and spat in tomorrow’s porridge. The Crown’s scientists came and went. I stayed, in case I was needed, but I wasn’t. The Crown wanted to show the tape of the police interview but no one knew how to work the video player. I know it makes me sound ancient, but DVD players weren’t widely used at that time. Rather than allow us to try to work it out for ourselves (three barristers, a solicitor, a judge, three forensic scientists and an assortment of police officers who must have had to deal with videotapes and players on every shift), court was adjourned for half a day so that a technician could drive from Aberdeen to fix it. Only a certified technician was allowed to touch it. The technician duly arrived, pressed a switch, the VCR started to work and we all got back to the trial wondering how life had become so mad and why the technician couldn’t have told us over the phone which button to press.

  There were many other things about the case that were bizarre including some of the circumstances (the defendant was found guilty; the defendant went to prison; the case was appealed; the defendant was released). I can’t really say much more because I’m not sure if there might be some other ongoing issues with it but another odd incident occurred during the original trial. A mobile phone rang (very quietly, I might add). The judge stopped the proceedings and demanded that the offender place at least a pound, but preferably a bank-note of some denomination, into the charity jar he kept on the bench. I leaned over to the solicitor and commented that this was indeed a strange occurrence. He leaned back and said, ‘It’s just as well we’re not in the court room next door — the judge in there puts people in the cells for an hour if a phone goes off in his court, even if you’re a QC.’

  Chapter 11

  Pollen

  Today, I am wondering what happened in my life that meant my working day was reduced to boiling the snot of dead people. Because that is what I am doing. I have eight test tubes, I’m in the laboratory and I’m mentally battling with myself about what the contents of these tubes represent. No matter how I look at it, I can’t escape reality: it’s snot from dead people. This isn’t some kind of punishment inflicted on me because I was naughty or did some thing wrong. This is part of a research project I dreamed up, along with some colleagues from England, while we were having a beer in the bar during their 2009 visit to give evidence in the Bain retrial. The reason we started to discuss dead people’s snot is because we wanted to see if we could come up with a method to collect pollen from the nasal passages of the deceased that was less costly, time consuming and invasive than the previous method.

  Pollen analysis is an area of forensic science that doesn’t really get the coverage it deserves. That’s partly because it seems to have been painted as technically difficult. However, pollen analysis (and I use the term ‘pollen’ here to include spores as well) is not really any different from other types of trace material. The same factors have to be taken into account when considering collection, sealing of items and examination/processing at the laboratory. The real skill comes in the interpretation because it requires knowledge of botany, ecology, crime scene examination and the forensic arena, in order to be able to make any sense out of it.

  When you look out at a meadow or garden in spring time, the sight that meets the eye is of regeneration — new growth, flowers and pretty colours. Floating in among the beautiful posies, billowing grasses and flowering trees are masses of reproduction bodies — pollen and spores. Because not all of those reproduction bodies go on to make new plants, the ones left over are the trace deposits that can be picked up and used by human beings for forensic purposes or for heating our homes. Pollen, spores and microscopic particles made of a compound called sporopollenin, form a component of the fossil fuels we burn in our fireplaces, or in coal-fired power stations. Pollen and spores are also used in the petroleum and gas industries to help find layers of underground rock that might contain those fuels. Of course, those pollen and spores are essentially fossils but the modern ones floating around in the air and settling on surfaces all over the planet are the ones most likely to be encountered in forensic casework, as well as being the ones that cause hay fever. From my academic research perspective, pollen is most commonly used to reconstruct past vegetation communities, which, in turn, tell us about climate and environmental setting at the time the pollen was deposited. For example, I know all about how Auckland’s vegetation changed over the last one million years and how it reacted when tonnes of volcanic ash rained down on it from the Auckland and central North Island volcanoes. It’s interesting, it adds fuel to the climate change debate, but it’s not often going to solve any crimes. We have to think differently for crime solution.

  From the perspective of people who are murdered, their last breath may well contain pollen from the place where they took that last breath. Knowing what plants that pollen represents can some times help investigators determine what happened to a person before and/or after they died. Those of a delicate disposition may want to skip this next bit but going back to my cunning plan of boiling dead people’s snot, the problem with the previous method of collecting samples from nasal passages was that it was very invasive. It involves removing the top of the skull with a saw, removing the brain (this often occurs during post mortems anyway), peeling off the basal lining of the skull, breaking through the bony base of the skull and into the nasal passages. The corpse is then turned on its side, a warm water and shampoo mixture is flushed through the nasal passages and the emergent liquid is caught in a bowl as it exits the nasal passages. This procedure requires at least two people, one of whom is usually a forensic pollen expert. Because forensic pollen experts aren’t routinely present at postmortems, arrangements have to be made for the pathologist, pollen expert and often a police officer to be present — this takes time and costs money because the pollen expert might have to travel from a long way away. The pollen expert also has to bring a whole heap of kit with them to get the job done, just in case the mortuary doesn’t have that particular equipment.

  Delaying post mortems is not desirable, because not only does it delay the investigation, it also delays the time until the body can be released to the family for the funeral. On a personal note, I would also prefer that if a pollen sample had to be collected from a body that the minimum amount of destruction be done to that body.

  Another reason why I thought long and hard about how to collect pollen samples from noses without having to remove brains was purely selfish: I don’t want to attend any more post mortems than absolutely essential. A post mortem is a fascinating experience and I’ve always been totally absorbed with how the body functions. One problem, though, is that I have a very sensitive sense of smell and mortuaries and dead bodies usually have strong smells associated with them. The other thing is that I’m not keen on seeing skin being cut.

  I know this because the first post mortem I ever attended resulted in me going very grey as the blood drained from my face, down through my torso and into my legs where it was quite happy to stay. The only thing that had happened at that stage was the pathologist leaning towards the deceased’s eyes and pulling them back with tweezers to see if the blood vessels were burst — a classic confirmation that
the chap had died as a result of hanging (probably a pretty good clue was the weird angle of his neck). Although my brain really wanted me to look because it was interesting, my basic consciousness decided it was a very bad idea and just shut down, which led to the buckling legs and the smirks from the mortuary assistants who’d been watching me very carefully to see how I’d react. I guess one of them lost the bet about whether or not I’d keel over. After that, the skin was cut and ribs of the deceased were cracked with a special tool. Luckily for me, I was being assisted to a stool while that bit happened.

  After I’d recovered, though, the rest of the post mortem was just amazing. The brain really looked like brains do in books, which might sound silly but it’s the same as seeing Big Ben or a real kiwi for the first time — they really do look like they look in the pictures. The kidney cross-section was intricate; the intestines were just all over the place like unstrung sausages. I came away from that post mortem fascinated, educated and horrified in equal measure. And embarrassed, because the pathologist was the same one who did the post mortems on Princess Diana and Dodi Al Fayed. He was very gracious about my temporary staggering and never mentioned it again. He must see that sort of reaction all the time.

  So here I am today, boiling snot from dead people to see whether our new, non-invasive technique recovers as much pollen as the old brain-removing approach. I’m happy to say that it does, which, if people use it, means less time wasted at post mortems, less cost and, for me, less chance of having to go to post mortems at three in the morning.