Cool science

Some of us Scibloggers were called ‘cool’ this week by the Taranaki Daily News – Cool science. It is cool indeed to be called a cool scientist.


Don’t accept the forensic science at face value

Here in NZ the Police are now stopping people who they suspect may be driving whilst impaired through the use of drugs. I’ve written before about drug driving and the impairment tests and I again reiterate the importance of not accepting the blood sample analytical results at face value, particularly in relation to cannabis. Lawyers in NZ seem to accept the science as reported by ESR in casework at face value. Whilst I’m not suggesting that ESR mis-reports any science, it must be remembered that the scientists at ESR base their reports on the information provided to them by the Police. Quite often a Defendant will be willing to tell something to their lawyer that they weren’t prepared to tell the Police – for whatever reason. This can have a marked effect on the interpretation.
Rather than leave it to chance for cross-examination in the witness box, lawyers should be asking experts to re-examine the science. Without such re-examination, re-interpretation is left to the scientific knowledge of the lawyers….
I have been unable to find an independent forensic toxicologist in New Zealand – it must therefore be accepted that if the Defence is to have a level playing field in court, funding must be provided for an independent Expert based overseas.
Many people will think that most people who are arrested for any reason are guilty of some crime, so does it really matter whether or not they get Experts to speak for their side of the story? Isn’t it just a waste of taxpayers money? But just remember that anyone can get arrested – wouldn’t you want access to good Experts if you, or one of your family, children or friends was arrested and charged with a criminal offence?

Can NZ juries do the job with which they are charged? Law review

I don’t normally get involved with the world of comment on whether or not juries are capable of doing the job they are there to do because, at the end of the day, my job as a forensic scientist does not involve having an opinion on the Ultimate Issue, i.e. whether or not the Defendant is guilty of any charge(s).  However, there have been several high-profile New Zealand cases this year in which juries have been criticised by the media for being incapable of making fair and informed judgments. Juries, of course, have no way to comment.

I also don’t normally advocate just inserting a link into a blog, but again, this issue seems to be a relevant one.  The matter has now been reviewed by University of Otago law professor Kevin Dawkins, so, this article caught my eye today and I think it is worth a read: Jury system may not be perfect but could benefit from some refining. I will leave you to read it and make up your own mind.

DNA law changes in NZ

The NZ government passed a law through this morning that allows the Police to collect DNA and fingerprints from any person that they will charge Parliament passes DNA law. This is different from the current situation where only people who are convicted of a crime that carries a sentence of seven years imprisonment or more have their DNA collected.

As I’ve said previously, personally I have no problem with the NZ Police being given greater powers to collect DNA samples from individuals who will be charged with an offence. At present, DNA and fingerprints are collected from everyone who is arrested in England & Wales, regardless of whether or not they are eventually charged. This is currently the subject of heated debate and the government is today in a position of having to make a decision about when and what samples from people who are essentially innocent of any crime are to be removed from the database: see here. Some would say that perhaps the UK has gone too far.

Compared with the UK, the NZ database is relatively small and even with the additional samples being added as the law will now allow, it will remain relatively small. Concern has recently been raised in the UK about whether or not the DNA database has got so big, interpretation is becoming problematic see here – as at 31 March this year, there were DNA profiles from 4.86 million individuals on the database ( Particularly from the first link I note that “there are strong statistical arguments against the application of such a large database in forensics. Not only does the complexity of storing and searching such a large body of data increase substantially with the size of the database, but so too does the probability of errors, duplicates and false entries. Moreover, the chance of getting a false positive match is also much higher, simply due to the vast number of comparisons involved and the percentage of the population who have similar (or identical) DNA fingerprints.”

Cold case reviews in the UK have shown that successful matches can be obtained from people who have previously committed a serious offence and then more recently have had to provide DNA and fingerprints in relation to minor offences such as traffic violations. The beauty of cold case reviews is that DNA can solve crimes that occurred before the use of DNA as a crime fighting tool became widely known. A lot of criminals who committed offences in the 1990s or before probably didn’t even realise that they deposited anything worth collecting at the crime scene. Only the foresight of police and scientists meant that samples were collected and are now available for testing. In NZ, the first case that springs to mind that could have been solved one way or the other if samples had been kept for future analysis is that of David Bain, but samples were not kept and now cannot be analysed.

Overall, I think that if managed correctly and with an eye on what has happened in other countries that have already been along this route, the use of such a DNA database in current and cold cases is potentially of great assistance in solving crimes. It is, however, important that users and interpreters of the database understand and acknowledge any potential failings as the database grows and not blindly accept everything that is suggested by the database. Experience in the UK has told them not to rely solely on DNA hits to successfully prosecute cold cases and I personally am always more comfortable with a multi-disciplinary approach to crime investigation.

Forensic science cost-cutting could cause errors, say experts

This is an article from the Guardian, 13 September 2009.  It basically outlines what has happened in England & Wales and what we, here in New Zealand, should be glad has not happened – yet.  Although I am sure some would argue that there is a need for the stranglehold of ESR (the main provider to the NZPolice) to be broken, there’s no point if there is no viable, economic, sensible alternative.

“Police contracts that put pressure on forensic scientists to deliver low-cost investigations within tight timescales risk jeopardising quality and could lead to a miscarriage of justice, experts have warned.

Police forces have changed the way they obtain forensic science services for criminal investigations and now pick laboratories through competitive tendering.

That has led to forces typically employing firms that offer the lowest cost or quickest turnaround time for testing evidence, according to Clare Stangoe, principal scientist at Forensic Access, a leading provider of forensics services. The murder and sex crimes specialist said that whereas before scientists were given “the time they need”, they might now have to deliver results within three days, with the laboratory facing a fine if they are late.

“The danger comes where arbitrary time frames are put on work,” Stangoe said. “Too much pressure put on scientists to do the work so quickly [means] that they may only do very specifically what they have been asked … It could lead to mistakes being made or not enough being done to investigate something properly.”

She added: “There’s a lot of concern in the community [of forensic scientists], that you don’t want miscarriages of justice to take place in the future.”

Her comments were backed by Helen Kenny, who as branch secretary for the Prospect trade union at the Forensic Science Service represents 1,200 forensic scientists. She said demanding contract terms could encourage scientists to accept a “quick [DNA] match” rather than carry out the “best possible investigation”.

“Forensic scientists have concerns about the pressure on turnaround and price,” she said. While emphasising that the FSS had not told its scientists to compromise on quality, she said such pressures “can’t be good for the criminal justice system”.

The FSS used to have a monopoly on police forensics work, but competitive tendering has exposed it to commercial pressures and in June it announced plans to axe 800 jobs, to the anger of Prospect.

Professor Allan Jamieson, director of the Forensic Institute in Glasgow, said that the principle of competitive tendering was the right one but that it needed refinement.

“It’s the best way, done properly, to ensure the proper spending of public money. However, you need quality assessment as well as financial assessment,” he said.

Jamieson said there were similar pressures on the defence side, where the legal aid board would instinctively favour the lowest cost option.

The Home Office said: “Commercial suppliers have provided an excellent service in forensic analysis to the criminal justice system for many years. There is no evidence to suggest that that should change in the future.””

Roadside drug testing; drug driving

One of my earlier posts commented on drug driving, the recent law changes in New Zealand and the new ad campaign in England & Wales.  The answer that everyone would like (apart from the people who actually take the drugs) is a roadside device that can screen, say, saliva for the presence of drugs – the drug equivalent of a handheld breath alcohol testing device.

It is important to understand that one of the reasons it is so hard to produce a device like a breath tester but for drugs is that the blood alcohol level is prescribed in law and can be so prescribed because of the way alcohol behaves once it enters the body.  Although the effects of alcohol vary within and between individuals, there is still a general level upon which the experts agree that people become impaired through alcohol consumption.  The rate at which alcohol is eliminated from the body is also relatively constant.  The same cannot be said for other drugs, particularly if more than one drug is taken at a time.  Concentrations of drugs and metabolites in saliva and blood also are not directly comparable.  It is not always possible for science to provide a perfect answer to a problem within society.  Be assured that the companies developing the technology for roadside drug testing are flat out developing a workable unit for use at the roadside by Police Officers – I’ve seen some of the prototype work and I’m sure they’ll get there in the end.  In the meantime, the new changes to the New Zealand law should, I hope, be successful.

Drug driving and impairment testing

Drug driving is illegal in many countries including New Zealand and the UK.  New Zealand has recently (June 2009) changed the law in order to increase the rate of successful prosecutions .  These changes, which come into force in December 2009, include giving the Police the power to conduct roadside impairment tests.  Such tests were introduced in England & Wales in 2004.  As a forensic scientist working largely for the Defence at that time, these changes resulted in a) more casework coming through our door; and b) more successful prosecutions.  As long as the Police covered off all relevant points it was very unlikely a case would fail.

My involvement 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 of the Driver at the time in question;
  • 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 they had grounds for arrest and transfer of the Driver to the Police Station.
  • once at the Police Station, a medic is required to examine the Driver.  This allows the medic to rule out any medical cause for any impairment observed by the Police Officer at the scene – the Driver usually has to re-do 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.
  • the blood sample would be analysed to detect the presence of a range of commonly-encountered drugs (prescription and illegal) that 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.

All of the above had 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 & Wales being successful (in my experience at least), the UK government has announced a new ad campaign warning of the dangers of drug driving. The adverts will 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.  Drugs affect difference people in different ways but can be generalised.  For instance, 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.

People cannot control how drugs affect them, particularly when combined, such as cocaine and alcohol.  Time will tell whether the law change in New Zealand helps combat the problem.