Posts Tagged Forensic Casework experiences
Hair, science and crims Feb 28
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Analysing hair for criminal casework purposes has had some new developments recently, as reported in Forensic Science International. For your delectation and delight, and as the journal has a log in, I have decided to share some of the papers that deal with day-to-day issues to which we can all relate:
In Sweden, if someone is convicted of either drug crimes (described as “petty”, presumably referring to possession only) or drug driving, their driving licence can be revoked. In order to regain their licence the driver must prove that they have been drug-free for a given period time. As anyone working with drug offenders knows, it is relatively easy to pass a drug urine screening test: either abstain for a relatively short period or cheat the results by using someone else’e urine (there’s a black market for ‘clean’ urine – think Gattaca). When drugs are consumed, the pattern of use is recorded in hair, particularly in head hair. A Swedish study has looked at the viability of using hair analysis instead of urine analysis when assessing whether or not to return someone’s driving licence to them. Interpretation has several issues (including understanding and knowledge of the screening method limitations) but the people being tested apparently approved of hair sampling “considering it a better means to prove their drug abstinence. In addition, both the clients and the clinicians thought hair sampling easier than urine sampling.”
(Hair analysis for drugs in driver’s license regranting. A Swedish pilot study, Pages 55-58, Robert Kronstrand, Ingrid Nyström, Malin Forsman, Kerstin Käll).
As with all cases where people have to prove drug abstinence by providing a sample of hair for analysis, it’s always interesting when they turn up to have their sample taken but have just come from the hairdressers where they had a Number 1…..
In Italy, a study has been completed to “investigate acute and chronic exposure to environmental tobacco smoke (ETS) in a cohort of young adolescents using urinary cotinine and hair nicotine testing after recent implementation of Italian smoke free legislation,” which has implications for everyone. The overall conclusions were that “due to the implementation of smoke-free legislation and information campaign against smoking, a significant trend toward low exposure to ETS was observed in this study cohort with no association between exposure to ETS and respiratory illnesses.” What I did find interesting was this: “Hair nicotine was inversely related to educational level of the adolescents’ parents” – not just the comment itself but the way it was phrased. It must have taken a while to phrase that appropriately…
(Assessment of exposure to environmental tobacco smoke in young adolescents following implementation of smoke-free policy in Italy, Pages 97-100, M. Pellegrini, M.C. Rotolo, S. La Grutta, F. Cibella, O. Garcia-Algar, A. Bacosi, G. Cuttitta, R. Pacifici, S. Pichini)
Finally, a French study investigated something that I find to be utterly fascinating: “Heroin markers in hair of a narcotic police officer: Active or passive exposure?” I think the Abstract just says it all without any need of assistance from me: In “March 2007, a police officer (46-year-old man) and a clerk (37-year-old woman) were arrested and subjected to investigation on the charges of drugs of abuse trafficking. The loving couple was exploiting their administrative positions to make money with the resale of seized drugs. The laboratory was requested to analyse their hair for drugs of abuse. Hair of the 2 subjects tested positive for heroin by GC–MS. A few days later, analysis of hair obtained from 11 other police officers of the same unit was requested, in order to compare the results, as external contamination was proposed to account for the positive results. The aim of the investigations was to demonstrate that passive contamination could not occur for persons dealing every day with drugs of abuse with minimal caution and hygiene, and that the measured concentrations in the arrested subjects correspond to personal abuse. All the narcotic team tested negative, irrespective of the compound.”
And that’s this month’s round-up of Forensic Science International….
Veneer to the rescue! Feb 11
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There’s a man in China who’s very glad about varnish and veneer. Despite his fingerprints being found at the scene of a theft, he was discharged by the judge who was presiding over his trial for said theft (Driver nearly convicted for incidental fingerprints). The reason was because the fingerprints were beneath a veneer on a deity altar and had been deposited by the freed man more than ten years previously, at a time when he had been working for a company that made such deity altars. The altar was then bought by the victim of the theft, who took it home and from where it was later stolen.
The Court also believed the discharged man’s alibi – he was working as a truck driver at the time of the crime. The presiding judge thought it unlikely that he would have abandoned his truck on the side of the road to commit a random theft.
Case circumstances are so varied – no two are ever the same….
DNA evidence causes case to be dropped Feb 10
No CommentsPeter Williams QC topped off a successful legal career last week by successfully applying for the case of Zion King to be discontinued. The Crown supported Mr Williams’ application and the Judge granted it.
Zion King was charged with the murder of Chattrice Maihi-Carroll in March 2008 after the deceased was found with stab wounds on 21 January the same year.
Key points that resulted in the dismissal of the case were problems with the statements of Crown witnesses about when Mr King had told them he knew about the death – it seems the first statements indicated he had known about it before news had been released to the general public, which meant that he must have been involved with it. Further investigations showed that he had actually not known about it before everyone else.
Also crucial to the dismissal of the charges was the DNA evidence – or lack of it. Mr Williams pointed out evidential matters that supported his application for the case to be discontinued, as follows:
a) Reasonable possibility DNA excludes accused;
b) No forensic evidence against accused;
c) Accused had no relationship with deceased;
d) [not related to DNA];
e) Deceased suitor’s blood on pillow;
f) Unidentified male DNA on glass on kitchen bench;
Considerable effort was put in by the Defence team to investigate matters so that the above points (as well as others) could be supported. To quote Hawke’s Bay Today (because it’s not clear from the article who said it), “The case had [sic] revealed “how essential it is for defence to investigate independently”. I couldn’t agree more.
Cocaine on money, drug traces on banknotes Feb 10
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I was surprised at a news article in the English MailOnline, which states that Every British bank note is contaminated by cocaine within weeks of entering circulation. I wasn’t surprised about the cocaine issue, but about the fact that the media seemed to think this was new or unusual.
I’ve been working on cases involving drug traces on banknotes since 2002 and even back then 95% of English banknotes were contaminated with traces of cocaine. To my mind, the most comprehensive database dealing with drug traces on banknotes is compiled and maintained by a company in the West Country of England. When I left England in 2008, practically 100% of banknotes in the database were contaminated with cocaine (and not just contaminated but high levels of contamination), less were contaminated with MDMA (from Ecstasy) and amphetamine, and less still with diamorphine (from heroin) and THC (from cannabis). The company is question is not one of the mainstream prosecution laboratories but a standalone organisation that has developed specific equipment to deal with analysing traces of drugs on all sorts of items including vehicles, clothing, mobile phones and, of course, banknotes.
It should be remembered however that the traces of drugs we’re talking about here are so minute that they can’t be seen with the naked eye. To put it into perspective, if one took a grain of salt and divided it into 1,000 pieces and then if one took one of those pieces and divided again into 1,000 pieces, this is the level of contamination that the anaytical equipment can detect – it’s teeny, teeny tiny. The other way to look at is if the total amount of drugs present on one million English banknotes (each contaminated with this small weight) was bulked together it would amount in size to no more than a single grain of salt.
Drug traces on banknotes can be extremely valuable for assisting Police and Customs to determine whether or not seized quantities of money have been involved with the drug trade but cocaine has always been a difficult one to interpret. Wouldn’t it be great if the technology could be applied in New Zealand, given that there is such a problem with P here?
The nasty job of identifying victims of mass disaster Jan 29
No CommentsHow are victims of disasters like the Haitian earthquake identified if they are unrecognisable when they’re recovered from the debris? By using forensic science techniques.
As with the South East Asian tsunami of 2004, Hurricane Katrina in 2005 and so many other situations, dozens of bodies need to be identified as fast as possible.
I heard a forensic dentist talk about the terrible working conditions in Indonesia where bodies were stored in unrefrigerated shipping containers (no refrigeration units), waiting to be identified – time was clearly of the essence for multiple reasons – closure for the family before the bodies rot, getting through the bodies before they rot so badly that they’re difficult to handle. Because they had such limited facilities, the dentists and anthropologists rigged up a portable x-ray machine to some school chairs they found in the debris so that they could elevate the machine high enough over the bodies so it could be operational. Bodies like these are not only damaged but often caked in mud, making visual identification not only traumatic for the family but also extremely difficult from a practical perspective and sometimes impossible.
In situations of mass disaster, relatives of the missing also provide DNA samples or are asked to bring along hairbrushes or toothbrushes of their family members so that DNA samples can be collected and compared with cadavers. Dental records are acquired where possible.
I was on a training course in July 2005 with three of the first firefighters who had attended the London Tube bombings two days earlier – they talked about the lack of air in the Tube tunnels, the ambient heat, the smell, the hours they spent down there logging the scene, searching for people and finding bodies. I talked with people whose office windows had been blown out by the London bus bomb in Tavistock Square – crime scene examiners came and took swabs from their office furniture and the roof because knowing the extent of the damage (i.e. spread of the human DNA) helps map the bomb site and determine things like location of the bomb relative to the passengers – vital for working out what happened and possibly for use in prosecution. I don’t think the people who had to go and work in that office will ever look at the walls in the same way again – even the best crime scene cleaners can’t wash away what stains the mind.
The people who go to scenes of mass disaster are a rare breed. CSI makes this job look sexy. It’s not.
Meth driving Jan 26
No CommentsHow hard is it for a Police officer to determine whether a driver might be off their trolley because of methamphetamine abuse? Some might say that if you see it often enough, you recognise the signs.
How hard is it for a forensic toxicologist to reconcile different driving behaviours as being attributable to meth use? Possibly very difficult, if no blood sample is taken. However, New Zealand’s law now allows for a blood sample to be collected from drivers suspected of driving whilst impaired through drugs (see previous posts: Drug driving and impairment testing, Roadside impairment tests; drug driving, Don’t accept the forensic science at face value). Which is just as well, given the enormous variation in behaviours that can be exhibited by meth users.
I would expect most people in NZ would think that a driver who was on P (pure methamphetamine) would be tanking down the motorway at 150 kph with the Police in hot pursuit, as per last year’s events involving the accidental death of a courier driver who was caught in the cross-fire between Police and an armed driver. However, an article in last month’s Science & Justice shows just how varied the effects of P can be.
The article’s author, Nikolas Lemos*, writes of two separate cases involving drivers being stopped by Police.
The first case involved a relatively placid, co-operative man who drove somewhat erratically but was slow (only about 30 miles an hour) and was tail-gating the car in front. Police asked him to stop and he did.
The second case involved the Police in a high-speed car chase with a driver and a stolen sports utility vehicle. After racing along roads at speeds in excess of 100 miles an hour, the driver then leapt from the moving vehicle, leaving a female passenger to crash, along with the vehicle, into police cars. Police chased the driver and tried, unsuccessfully, to subdue him with a conductive energy weapon (which I assume means a Taser). After being Tasered (is that a real word?) another two times, he was dragged kicking and screaming into custody.
Two more dissimilar descriptions of P users you couldn’t imagine but the blood methamphetamine concentrations of both drivers were comparable as were their heights and weights. Just goes to show just how unpredictable P can be.
* As the article is behind a subscription wall, the full reference is: Lemos, N. 2009. Methamphetamine and driving. Science & Justice, 49(4), 247-249. Abstract: Methamphetamine incidence in driving under the influence cases in the City and County of San Francisco is a significant and on-going challenge. Two methamphetamine positive driving cases are presented herein demonstrating some similarities in observed signs and symptoms and drug blood concentrations but which are also characterised by very different driving styles and behaviours towards the police officers when encountered on the road.
The article also discusses other issues such as the field impairment tests and analytical results.
Cocaine on banknotes Jan 10
No CommentsI was surprised at a news article in the English MailOnline, which states that Every British bank note is contaminated by cocaine within weeks of entering circulation. I wasn’t surprised about the cocaine issue, but about the fact that the media seemed to think this was new or unusual.
I’ve been working on cases involving drug traces on banknotes since 2002 and even back then 95% of English banknotes were contaminated with traces of cocaine. To my mind, the most comprehensive database dealing with drug traces on banknotes is compiled and maintained by a company in the West Country of England. When I left England in 2008, practically 100% of banknotes in the database were contaminated with cocaine (and not just contaminated but high levels of contamination), less were contaminated with MDMA (from Ecstasy) and amphetamine, and less still with diamorphine (from heroin) and THC (from cannabis). The company is question is not one of the mainstream prosecution laboratories but a standalone organisation that has developed specific equipment to deal with analysing traces of drugs on all sorts of items including vehicles, clothing, mobile phones and, of course, banknotes.
It should be remembered however that the traces of drugs we’re talking about here are so minute that they can’t be seen with the naked eye. To put it into perspective, if one took a grain of salt and divided it into 1,000 pieces and then if one took one of those pieces and divided again into 1,000 pieces, this is the level of contamination that the anaytical equipment can detect – it’s teeny, teeny tiny. The other way to look at is if the total amount of drugs present on one million English banknotes (each contaminated with this small weight) was bulked together it would amount in size to no more than a single grain of salt.
Drug traces on banknotes can be extremely valuable for assisting Police and Customs to determine whether or not seized quantities of money have been involved with the drug trade but cocaine has always been a difficult one to interpret. Wouldn’t it be great if the technology could be applied in New Zealand, given that there is such a problem with P here?
Scientists and our opinions Dec 07
No CommentsThis post follows on from a recent post by Grant Jacobs (Scientists on TV: referees of evidence or expert’s opinion?) and associated comments.
In my opinion, if an expert is presenting information to a court, the court setting doesn’t matter, the manner in which the scientific findings are presented should be the same, regardless of the forensic setting – reproducibility, reliability, impartiality, duty to the court not to those instructing, not having an opinion on the Ultimate Issue (guilt, innocence or other final outcome to be decided by the Trier of Fact and no-one else). The things that distinguish how findings are presented are the rules that relate to individual courts. As a guide, the High Court Code of Conduct for Expert Witnesses is the minimum I would expect of any consultant I used, regardless of the court – these Rules relate to the NZ High Court. (I have previously written about the differences between scientific findings and evidence).
The UK has the most advanced set of procedures that I have encountered to-date – and, having worked with them for some years, I believe they are excellent. Civil procedures are covered by Criminal Procedure Rules (CPR) Part 35 and Part 35 Practice Direction. Criminal procedures are covered by the Criminal Procedure Rules (CrPR) Part 33. These detail how to write reports, how the court should treat Experts, how the court system should work and what the Expert can expect, to name but a few. It seems very regimented but it is designed to create and maintain consistency in standards.
Once the scientist/expert is familiar with the CPR Part 35 and CrPR Part 33, it makes life much, much easier. It allows the courts to believe the findings more easily because before the findings can even make it into court they’ve been through a rigorous checking procedure, as has the Expert. Having experience giving evidence helps as well of course – the more experience, the better (although that doesn’t meant it’ll get easier with time – it doesn’t).
So, in conclusion, if a scientist can learn to use these tools of procedure for casework and preparation of reports, maintaining control of an interview should seem much easier! Although, lest we forget, there are no rules for interviews….
Nifty forensic science techniques – real CSI Nov 24
No CommentsHow to remove a lightbulb using a kid’s dart is described as “a high tech process to remove a light bulb without damaging latent prints using a toy dart” (some dry humour is always a good thing in forensic science) – this is the sort of forensic technique that is not only interesting but extremely useful….and it’s exactly how it sounds!
Other useful videos on the same page include How to lift a dusted fingerprint off a body or a live person and How to use a stun gun as an electrostatic dust lifter. These videos are short and highly informative. Recommended viewing for the interested and the budding crime scene investigator.
Part 3: CSI effect/forensic science jobs Nov 20
No CommentsI have previously talked about how to get a job in forensic science and how CSI has skewed the image the general public has of forensic scientists (see job in forensic science, retrain, real CSI effect, speed and effect of science, job in forensic science plus others – it’s something about which I have strong feelings…). This is a good and brief article dealing with Bob Shaler’s opinion on forensic science, CSI and what it means to get a job in forensic science: Is Forensic Science on TV Accurate?. Bob Shaler was the man charged with handling the DNA identification of the World Trade Centre bombings so he knows his stuff. Disappointingly for many, when he says “I was a crime lab guy, but I was never the person portrayed on TV.” “That person doesn’t really exist.” – it’s sad but true.
