Murder and Atoms

Richard Hill and fellow hikers were walking in the Yorkshire Dales, about an hour’s drive from where I live, when they stopped to take a photograph. He stood by a stream near to the Sell Gill Holes caves in Pen-y-ghent but didn’t notice, just behind him, was the face-down body of a half-naked woman. They were two kilometres from the nearest road and the body had likely been dumped on higher ground one to two weeks earlier, before being washed down by torrential rain over the previous 24-hours.  It was the decomposing body of a 25-35 year old woman wearing green Marks and Spencer jeans, socks and a wedding ring. This was back in 2002 and an E-fit picture and police enquiries made at that time turned up nothing. Oddly, no one meeting her description had been reported missing anywhere in the country.

Locals affectionately called her the Lady of the Hills, they gave her a funeral and buried her in the village cemetery. The case went cold, until the new forensic technique of stable isotope analysis arrived on the scene. 

The chemical elements listed in the periodic table are defined by the number of protons in their nucleus, one for hydrogen, two for helium, and so on until the 92 protons of uranium. Although atoms of any given element always have the same number of protons, they can have different numbers of another sub-atomic particle, the neutron. All hydrogen atoms for example, have one proton but one in 6,250 also has a single neutron and about one hydrogen atom in a quintillion has two neutrons. This subclass of elements, defined by the number of neutrons, are called isotopes. Those hydrogen atoms with one proton are an isotope of hydrogen called protium. Those atoms with one proton and one neutron are an isotope of hydrogen called deuterium. Those atoms with one proton and two neutrons are an isotope of hydrogen called tritium. And as the atom packs in more neutrons, so its mass increases, protium with a mass of one, deuterium with a mass of two and tritium with a mass of three. Chemists identify which isotope is which from its atomic mass, including it as a superscripted prefix to the elemental symbol, such as, 1H for protium, 2H for deuterium and 3H for tritium. The periodic table, that we are all familiar with, lists only the elements themselves but behind each of the elemental boxes is a plethora of isotopes.

The chemistry and reactivity of isotopes of the same element are almost identical, prompting their discoverer, Frederick Soddy, to say “put colloquially, their atoms have identical outsides but different insides.” The neutron does have some effect on the behaviour of the isotope and they separate out slightly under the right conditions. Take a spoonful of water from the Arctic or Mid-Pacific ocean and the isotopes of oxygen and hydrogen will be slightly different. Water with lighter isotopes is the first to evaporate, leaving behind seas enriched with heavier isotopes in warmer climes. Pour a glass of water from your tap and the blend of 1H216O, 1H217O, 1H218O, 2H216O, 2H217O and 2H218O depends upon where on planet Earth your tap resides. Similar effects can be seen with all the isotopes to differing degrees, and as those isotopes are taken up into the body, they leave an atomic trail of breadcrumbs as to where you’ve been. Isotopes incorporated in tooth enamel is locked in for life and so reveal where you were raised as a child. Isotopes in hair reflect more recent travels.

The forensic scientist and author of a 2010 book on forensic isotope analysis, Wolfram Meir-Augenstein of Robert Gordon University in Aberdeen, arranged to have hair, teeth and bone from the Lady of the Hills analysed for isotopes of carbon (13C), oxygen (18O), hydrogen (2H) and nitrogen (15N). Those in her hair matched proportions found in North Lancashire or South Cumbria and given the rate of hair growth she must have lived close to those areas in the time immediately leading up to her death. Isotopes in teeth and bone however, indicated she was from Thailand. Was she a so called Thai bride? 

Enquiries in Thailand eventually identified her as Lamduan Armitage new Seekanya, who had married in Thailand and then moved to Portsmouth, Rugby and then to Preston in Lancashire consistent with isotope analysis of her hair. DNA comparisons with family members in Thailand confirmed her identity last year.

As with so many other cold cases, her killer has not been identified. Police have said her husband, who lives in Western Kanchanabur, Thailand, is not a suspect but the Thai Examiner expressed frustration with the investigation. The British Newspaper The Sun, is campaigning to bring the culprit, whoever that may be, to justice. 

Isotopes can only go so far but without them it’s unlikely the women buried in the Yorkshire Dales would have ever been identified. And that has to count for a lot. I hope this blog post becomes out of date quickly, and this cold case can indeed be closed.

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