Friday, 20 November 2015

Following footprints

Nobody would claim that The Institute is at the centre of things.  So when we get a visiting speaker, I do my level best to turn up and also encourage any students who are under my wing within earshot to come along too. What the visitor has to say is surely going to be more interesting than the same-old-same-old drone from the likes of me. Partly that's because the visitors are not a random selection of the community; they are people who have a reputation for being articulate. They also get to be invited by someone on the staff who thinks their material is relevant and interesting to one or more of our student cohorts. We've had
This week we had a talk from Niamh nic Daéid, newly appointed Professor of Forensic Science at the Centre for Anatomy & Human Identification [CAHID] in U Dundee. She came from a 20 year posting in U Strathclyde where she became the first woman in that venerable institution's history to be awarded a personal professorship. She wanted to be an archaeologist when she left school but didn't get good enough grades, so went to read chemistry, maths and physics at an Institute like ours. Her grades may have been unstellar but her determination was mighty and she went on to get a PhD from the Royal College of Surgeons . . . and later a BA in Psychology from Open University! Hat's Off!! We are exposed to a raft of forensic scientists on the TV, in which strikingly symmetrical young women sort through the crime scene with unbelievably sophisticated instruments and wrap up the case within an hour including 12 minutes for ad-breaks. We know that it's not really like that but that sort of nonsense gets a great press, and persuades the gullible to sign up for 'forensics' courses at college. The other side of the forensic coin less so.  Who now remembers Dr Frank Skuse, whose " . . . conclusion was wrong, and demonstrably wrong, judged even by the state of forensic science in 1974" but whose tendentious interpretation of a Greiss test helped convict the Birmingham Six?  Who but The Blob remembers Lucia de Berk and Sally Clark being convicted of murder on the basis of dodgy statistical analysis?

Like any profession there will be a range of abilities between Dr Skuse and the perfect competence of TV fiction.  Prof nic Daéid pointed out that, in her profession it matters . . . rather more than if, say, your HR department cannot get contracts out on time and then sends them to the wrong people. Sending the wrong people to a lifetime is gaol is clearly a more serious issue. One of the skills you need as a top-gun forensic scientist is the ability to explain your findings and their scientific basis to ordinary people, and the pace and presentation of 'our' talk was right on the button: accessible to a raw 1st Year and informative to a professional biologist. FSs can be experts not only in blood-splatter, DNA identification and the chemistry of illicit drugs but also in the chemistry of combustible materials. This last is interesting because identifying how/where a fire started could be the basis for a criminal conviction but seeing how the fire spread is more about building regulations, health&Safety and public good.

Good FSs continue the traditions of Sherlock Holmes in having a technical expertise in written materials. But 70% of their work in this field is puzzling out what was written on the sheet of paper above the one which has been retained as evidence.  That doesn't require any sophisticated instruments, nor does matching a footprint in two different locations, but both can be useful in cracking a case.  At the techie end of the tool-box, there are 8 different protocols for making methamphetamine, each of which will leave a characteristic trace among the impurities that come down with the drug. To those in the trade, this chemical signature is almost as a good as a finger-print for identifying the lab where the drug was made.  How do they know this?  They make serial batches of the drug using each protocol and then run the results through analytical instruments and keep pictures of the output as 'standards'. Using similar standards, you can determine whether a fire was caused by unleaded petrol or kerosene or LPG which will tell a lot about whether arson is likely. That's criminal, but nic Daéid's people carried out research to show that 100% of boys and 80% of girls failed to wake up when a fire-alarm went off in their bedroom! That's a vital piece of data to inform public policy, parental behaviour and fire-alarm manufacture.

But perhaps the most worrying aspect of forensic chemistry is not identifying known substances - MDMA, gasoline, cocaine, haemoglobin, semen - at crime scenes but the ballooning number of chemicals which are new to the experience of the scientists involved.  If there are no standards and no standard protocols it is really difficult to stand up in court and stand over your findings. 350 new psycho-active substances NSPs have come on the market in the last few years and people in clubs and pubs are putting them in their mouths or up their noses without knowing how they act, where they are made or what they are cut with. That's a worry on many levels.
You can hear Niamh nic Daéid talking about similar material in a BBC interview. And she tweets. I particularly like her frequent use of the CEM Joad phrasing "It all depends on what you mean by . . .": until we know what we're talking about, there is very little real science going down.

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