01 September 2011

Isotopic Detective Work

I read about this forensic case in Chemistry and Engineering News, but found the abstract for the case study among the papers at the European Geosciences Union General Assembly 2011: “Stable Isotope Profiles from a Lock of Hair Provide Information of Illegal People Trafficking Route used by a Vietnamese Organised Crime Group” (PDF).

The study was conducted by Wolfram Meier-Augenstein and Helen F. Kemp of the Stable Isotope Unit of the Scottish Crop Research Institute in Dundee, and by Ian Brewster and Geoff Ronayne of the Gwent Police, “Croesyceiliog, Cwmbran.” (I’m assuming that’s Welsh, but I’m not familiar with the language of those ancestors.)

A young man with Asian features was left in the A&E department of a hospital in Gwent, South Wales (UK) by persons unknown and died shortly thereafter. A hit in the Interpol fingerprint database provided some information regarding the victim’s nationality but there was no record of this individual ever having entered the UK, at least not legally.

On behalf of Gwent Police, stable isotope analysis was carried out on a lock of scalp hair to generate chronological profiles for diet or nutritional changes as well as a recent geographic life trajectory.
Isotopes are atoms or ions of the same element with different atomic weights (i.e., numbers of neutrons). Different parts of the world have different concentrations of oxygen isotopes, which people and animals in those places take into their bodies. 
Moving from the oldest part of the hair (the tip) to the most recently formed part (near the scalp) the longitudinal 2H isotope profiles suggested the following. At 15 months prior to death, the victim spent approx. 2.5-3 months spent in Eastern Europe (most likely the Ukraine) followed by a direct move to Central Europe (e.g. Germany).

Subsequent to this move from the Ukraine to Germany, the victim lived in Germany for about 6-7 months from where he moved to the UK eventually to arrive at his final location of residency on or near the UK’s West Coast (South Wales). In contrast to the move from Eastern Europe to Central Europe, this move was not a direct transition from one location to another. This move either happened in stages over a period of 1.5 to 2 months interrupted by brief stays (< 0.5 month) at different locations, or the period between leaving Central Europe and arriving at the final location was characterized by frequent travel and change of location not necessarily related to or influenced by the final area of residency.

The information provided by stable isotope analysis in conjunction with enquiries carried out under Operation C#$#$## showed that the victim (a Vietnamese man) was indeed smuggled into the UK illegally and the trafficking route did run through the Ukraine via Germany into the UK. Once in the UK the victim was moved between Dover, London and Birmingham before eventually being settled down in South Wales, where he lived and was forced to work as Cannabis farmer for an organised Vietnamese crime group during the final 2.5 months of his life.
According to the C&E News story, a rival gang stole a big crop from this man, and his enslavers killed him as punishment. Those details would, of course, not be available through isotope analysis, so it’s quite possible the whole story could have come out through traditional police inquiries. But the match between those investigative findings and the isotopic readings confirms the value of both methods.

How soon will this technique show up in a television drama?

1 comment:

Melissa Stewart said...

Absolutely fascinating. Who knew science could tell us so much about a person's movements?