Expert Witness (19 page)

Although production of cannabis has reduced in New Zealand, it's still clearly going strong elsewhere. According to the BBC in 2009, up to £100 million of cannabis is grown in Scotland each year, and is worth more than the entire Scottish vegetable crop. Hydroponic cultivation seems to be pretty much the same everywhere and the use of entire buildings and hijacking the electricity supply for cannabis cultivation are common. I remember a case where a hidden room had been constructed in a house with an entrance through a secret door halfway up the stairs — although obviously not that secret because the police found it in the end but, still, when I saw the
photos it was all very Famous Five. Joking aside, though, large-scale cannabis cultivation is a very real problem with very real issues behind it — human trafficking, organised crime.

‘Skunk' is a strong, pervasively pungent variety of cannabis and is up to three times stronger than other types of cannabis. The British government recently reclassified cannabis from Class C to B to reflect the fact that skunk is now the dominant form of cannabis being sold on the British market. Some scientists are of the opinion that skunk may have a higher risk of causing mental health problems than other varieties. Skunk in the latter part of the first decade of the twenty-first century accounts for about three-quarters of police cannabis seizures; in 2003 the figure was much lower, at just 15 per cent. That's a massive increase, and just goes to show the skill cannabis growers have developed in hybridisation.

Aside from cannabis, New Zealand's other traditional drugs of abuse include P and heroin. Although the use of heroin isn't unusual globally, Kiwis used their famous number eight mentality and came up with a way of making heroin at home so they didn't have to bother with pesky imports at high risk of being intercepted by customs. This new home-cooking method, known not surprisingly as home-bake, started to pick up pace in the early 1980s when there was a sharp decline in the amount of heroin making it onshore.

Although heroin use continues here at a lower level, New Zealand's P problem, on the other hand, is now a significant industry. The manufacturing process mostly uses household items and commonly available chemicals. The use of P has
increased dramatically over the past eight years; when I went back to England in 2002 it hadn't really registered on the radar but by the time I got back in 2008, there were barely enough police and ESR experts to keep up with the casework demand, and both organisations now have teams specialising in P lab investigation. In much the same way as I would navigate around England using pubs as landmarks, a colleague marks his way around Auckland based on the P labs he's investigated — not a suburb is clear of them. New Zealand has world-class expertise in identification of P labs, clan lab clean up, yield calculations and property remediation/air quality testing. It's a marketable skill the rest of the world is needing to learn from us. Sad but true. By the way, a ‘clan lab' is the usual term these days used to refer to a clandestine or illegal laboratory, and has recently started making its way into the media and more common usage.

One of the problems with P labs is that even after they've been busted or dismantled, the drug itself lingers in the property. Painting or wallpapering over surfaces doesn't get rid of the problem because it just seeps through to the surface again. Full replacement of gib board or total demolition of the property are some times the only remedies. My serious advice when buying a house would be to make sure you have the air quality tested for the presence of methamphetamine residues
before
signing on the dotted line.

Because the application of forensic science usually takes place at the instigation of the police/Crown/prosecution, the types of science applied to casework are dictated by the capabilities and laboratory equipment available in each laboratory or organisation. This means that not all forensic
science laboratories are created equal. Take drugs cases, for example — there are a number of different methods available for examining drugs but they're not all used in all laboratories. A reasonable proportion of drugs cases I reviewed in England and Wales involved looking at the wrappings that contained the drugs. Makes sense really, when you consider that all drugs are wrapped in some thing or other.

Blister packs

Prescription drugs often arrive in these things. It's a terrible albeit descriptive name. I can't help imagining tablets erupting from the packaging in small floods of semi-transparent fluid, just like back in the days of popping blisters after finishing cross-country runs through the pouring rain at school. Contac NT, the starter product for making P, is produced in blister packs. Unless it is stolen or otherwise acquired before being packaged into blister packs, someone cracks the capsules out of the packaging, one at a time. Each capsule contains hundreds of tiny balls of medication about a millimetre in diameter. In case you're wondering, the same people don't then usually spend their time pulling the little capsules apart and emptying the balls into a bucket; they often just stick the capsules in a blender or a coffee grinder and flick on the power.

Kitchen foil

S
ome drugs, like ‘crack' cocaine, occur in lumps, known as rocks, and are often wrapped in small parcels of kitchen foil. Kitchen foil tears nicely and the ends of torn pieces can be matched together to see if smaller pieces originated from a larger piece or if they were ripped off a roll found in someone's
kitchen. Putting the pieces back together again is called a
physical fit
and it's a bit like putting together a jigsaw.

Cling film or food wrap

I visited a food wrap and poly bag factory once. I know it sounds like a bad school day-trip, but it was very entertaining. I saw barrels of tiny polymer pellets being melted down in giant vats, like some thing out of
Charlie and the Chocolate Factory
, and then blown though a circular mould called a ‘die', which makes an enormous long bubble of transparent polymer. The bubble is then cut to different lengths and rolled onto tubes to make food wrap or cut, folded and heat-sealed to make grip or zip lock bags. Knowing about the manufacturing process means we can consider colour, construction, size, optical properties, surface damage and chemical analysis of the polymer that forms the basis of the bag or food wrap. I haven't seen bag or food wrap comparison used very often in New Zealand, but it is a valid and very useful technique.

Along with alcohol, I find drug cases are among the most interesting, which I guess is a good thing professionally because it doesn't look like either is in decline.

A
policewoman once got very huffy with me because I demonstrated some of the English police's impairment tests during a presentation I gave in New Zealand. She said that I'd given the game away and now people would know what to expect when the police stopped them and I'd ruined it
all
. Firstly, people cannot control how they react to drugs so regardless of whether or not you know that you're going to be doing a one-leg stand or walking an imaginary line, if you're stoned off your trolley, you won't be able to do it properly. Secondly, the self-same tests have been shown in many real-life follow-the-police-around TV programmes, so they're no secret. Thirdly, the people I was addressing were business ladies of a certain age group, many of whom had never heard of some of the things I was talking about. I know you can't judge a book by its cover but I think it was unlikely they were the sorts of women who would be going into the toilets to snort a line of coke off the cistern with their platinum cards and then avoid doing a roadside impairment test on the way home. Although you never can tell.

 

Toxicology is the study of the fate of substances once they
enter the body, by whatever means — maybe the person ate them, drank them, absorbed them through their skin, breathed them in or injected them. Forensic toxicology is traditionally considered in relation to drugs but toxicology in its own right relates to many other compounds and could include anything from pesticides to gas inhalation or injection of heroin. The father of a colleague recently had a heart attack, caused by the absorption of a garden insecticide through his skin when he sprayed it on his hand. In that case, a hospital toxicologist would have been involved in determining the levels of chemicals in the patient's body. In theory, anything could be toxic; it's a question of dose and species.

A forensic toxicologist needs to know how a drug breaks down when it enters the body and how to detect those breakdown products (metabolites). The kinds of samples forensic toxicologists receive in the laboratory are not the sort that most people would want to handle just before lunch time: blood, urine, stools or body parts such as a livers or liquid from the eyeball. Toxicology is a vastly complicated world, dealing with the inner workings of the human body, and it takes a special set of skills to interpret toxicology results.

Toxicology crops up most commonly (in my experience anyway) in rape and sexual assault cases, murders, drug driving and prison urine screening tests, because no drugs are allowed in prison and the Powers That Be do check. One of the most familiar kinds of case involving toxicology is the date rape drug case, also referred to as Drug Facilitated Sexual Assault (DFSA).

Whether or not date-rape drink spiking is a real problem is a debate I have been following for some years. An article
in the
Daily Mail
at the latter end of 2009, which contained comment by a well-respected forensic toxicologist based at the London laboratory of the Forensic Science Service, suggested that DFSA is a minor problem which is far outweighed by the problem of heavy alcohol consumption. My casework experience bears this out. It is sad to say that I have been involved as a forensic science consultant on many rape cases in the past and pretty much all of them involved excessive alcohol consumption on the part of both parties. There was a single memorable case where an allegation of rape was made that didn't involve alcohol. However, the ‘evidence' of the assault had been falsified. In particular, the complainant said her jeans had been torn off her as she lay on a bed. Our experiments and research showed it was impossible for the jeans to have been torn in the way suggested. In fact, microscopic examination of the buttonholes showed that at least part of them had been cut.

As a woman, I am some times expected to champion the cause of women's rights and the problems of female oppression. Unfortunately, on the date-rape drug debate I cannot fight the corner and don't feel that I should be expected to do so. Rape is a very real problem and every thing possible should be done to deal with the issue and prevent it, where possible. However, excess alcohol consumption has skyrocketed in recent years, particularly among women. This to me represents the far greater risk. Excessive alcohol consumption will lead to varying degrees of incapacitation, even in someone who considers they can take their drink. To my mind, the closing line of the
Daily Mail
article says it all:
whatever the risks of the drink spiker coming after you — the chances are that alcohol will get to you first.

There are a number of drugs that could, theoretically, be used as a ‘date-rape' drug, the most common ones being those that induce sleep or stupefaction. All of the date-rape drugs (just like any other drug) have a residence time in the body, which varies. This is one of the key issues when considering the results of a blood sample analysis and it's where the skills of the forensic toxicologist come to the fore. Date-rape drugs (and others) can also be detected in hair. Of the cases where I have suggested hair samples be analysed, no date-rape drugs have been detected, with one exception. GHB (also known as gamma-hydroxybutyric acid or gammahydroxybutyrate) usually pops up, but that's because the body naturally manufactures the substance and its presence is to be expected in hair strand samples. It is therefore the variation in concentration that is important.

I'm not saying that drug-facilitated sexual assault doesn't occur, because it certainly does. I'm also not saying that there's little point in testing for drugs in hair samples because hair sample testing is one of those things that can't be faked, unlike urine, for which there is a thriving black market in ‘clean' samples. Hair sample analysis can also be critical to demonstrate the drug use history of someone who wants access to their children, but has been denied because of a previous drug abuse problem.

What I
am
saying is that a lot of people suffer at the hands of excess alcohol consumption.

Drug driving is a peculiar offence, not because it's uncommon, because it's not. An enormous number of people take all
kinds of drugs and then drive because they think they're OK, particularly with prescription drugs that may or may not be mixed with other drugs and alcohol. Drug driving is peculiar because it was traditionally a difficult area in which to achieve successful prosecution. It's not like drink driving, where there are legal limits written in to the law that, if exceeded, generally mean guilt of a specific offence. Alcohol is poured into the body and, once absorbed, is eliminated at a relatively constant rate; people behave in a reasonably predictable manner at given blood alcohol concentrations.

Drugs are a different kettle of fish altogether, because there can be significant variation in effects between different individuals, as a result of factors such as individual tolerance and history of drug use or habituation. The effects caused by a combination of drugs, including alcohol, can be exceedingly complex and cannot be predicted with any degree of certainty. Toxic effects depend on the degree of tolerance acquired by the individual concerned. This all sounds like what so many reporters tell me is a scientific cop-out, but it's true – we just can't say what will definitely happen when someone mixes drugs.

Drug driving is illegal in many countries, including New Zealand and the United Kingdom. New Zealand changed the law to try to increase the rate of successful prosecutions. These changes, which came into force in December 2009, included giving the police the power to conduct roadside impairment tests, similar to those introduced five years earlier in England and Wales. As a forensic scientist working largely for the defence at that time, these changes resulted in more casework coming through the door and more successful prosecutions.
As long as the police covered off all relevant points it was very unlikely a case would fail. My job was to assess whether or not the various points had been covered. These included:

• A witness (including a police officer) who could talk about the manner of driving at the time in question. Driving very slowly down the motorway usually attracts the attention of the police and might suggest the driver is under the influence of a depressant of some sort. Conversely, charging along the outside lane of the motorway at one-and-a-half times the speed limit will probably also attract someone's attention.
  
• The results of roadside impairment tests undertaken by the driver under the supervision and direction of a specially trained police officer. If the officer deemed that the driver had performed poorly then there were grounds for arrest and transfer of the driver to the police station. This is the subjective part of the procedure and is a function not only of how well the officer has absorbed the training but also how many impairment tests they've conducted and how many stoned people they've seen. A recent weekend police drink-and drug-driving operation in West Auckland involved stopping over 9000 vehicles. How many drug-impaired drivers were detected? None.
  
• Once at the police station, a medic was required to examine the driver. This allowed the medic to rule out any medical cause for the impairment observed by the police officer at the scene — the driver usually had to redo some or all of the impairment tests. If
  the medic formed the opinion that the driver was impaired through the use of drugs, a blood sample could be taken. Without this opinion, the taking of a blood sample was not allowed. I saw more than one case where the original reason for stopping the driver wasn't good enough in the eyes of the court and the driver hadn't exhibited many signs of impairment by the time the medic arrived, usually due to a two-hour delay because it was a Saturday night. In those circumstances, there was a chance the blood sample would be ruled inadmissible and the case would fall apart.
  
• The blood sample would be analysed to detect the presence of a range of commonly encountered drugs, both prescription and illegal, which can adversely affect driving performance. Some drug or metabolite would need to be identified in order to confirm that the driver may have been under the influence of drugs at the time in question. The blood sample result was not sufficient on its own. Finding metabolites of cannabis weren't good enough either, because they don't make a person high and they can also remain in the body for days or even weeks after the effects of cannabis have passed.
  

All of the above have to be in place for a successful prosecution. The law change in New Zealand seems to be along similar lines but only time will tell how well the police and the legal system deal with the changes.

Despite the law changes in England and Wales appearing to
be successful, in 2009 the government in the United Kingdom announced a new ad campaign warning of the dangers of drug driving. The adverts were to advise drivers that the police can spot the signs of whether someone may be under the influence of drugs using the tag line,
Your eyes will give you away.

It's true, of course. People cannot control how drugs affect them, particularly when combined, such as cocaine and alcohol. Depressants such as cannabis impair a driver's perception of distance, time and speed as well as restrict the ability to do two things at once, such as look for traffic and change gear. Cocaine is a stimulant and can cause people to take risks, such as driving at high speed in a dangerous manner. Both can have lethal consequences in today's traffic conditions.

I have given evidence in drug-driving cases on several occasions, most notably once in an appeal against conviction. The medic described the impairment tests, including a practical demonstration. The triers of fact (the judge and two magistrates) immediately called an adjournment, which suggests to me they were out the back trying the impairment tests to see how easy or hard they were. I can tell you that they're not some thing you want to try wearing high heels and a tight skirt.