DNA tests turn tiny crime scene samples into crucial new evidence
Murderers responsible for crimes dating back more than half a century could finally be brought to justice thanks to ground-breaking forensics techniques being pioneered by Scottish soil experts.
The team involved with high-profile cases, including the 1977 World’s End murders, are currently testing soil DNA profiling methods they believe will offer a new level of accuracy in pinpointing the origins of soil and plant residues linked to crime scenes.
Aberdeen-based Professor Lorna Dawson – who heads the soil forensics group at the James Hutton Institute – said: “We are working with the Crown Office, which is reviewing old cases that could be solved using the new methods and databases we have in Scotland, to see if we can take them forward,” she said.
“We are trying to help whenever we can, where there is soil, vegetation, plant material fragments that in the past were too small to be characterised.
“Now we can work with around 20mg of soil – the amount you could see under your fingernail – as opposed to a teaspoonful, which was previously required.
She added: “The dust is not allowed to settle on these cases as people are still missing and it is important we never stop looking for them. Their loved ones want resolution.”
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The challenges of bringing a cold case before a jury were highlighted in 2007 when the first World’s End trial collapsed after the prosecution failed to produce vital forensic evidence. But breakthroughs by Dawson’s team over the past five years were key to last year’s successful retrial of Angus Sinclair for the murders of teenagers Christine Eadie and Helen Scott.
Scotland’s senior law officer, Lord Advocate Frank Mulholland, praised Dawson and her team, who have worked on investigations across the globe – as far afield as Australia.
“Scotland is a world leader in forensic soil analysis evidence,” he said. “Dr Dawson’s evidence in the case against Angus Sinclair was very important in delivering justice.
“She gave evidence which proved that Helen Scott was still alive when she entered the field where her body was later found. This, together with other forensic evidence, disproved Angus Sinclair’s version that he had consensual sex with her in Holyrood Park a few hours earlier.”
Another case that made headlines was the murder of Robert Rose on the Orkney island of Sanday in 2009.
Dawson said: “Two of his supposed friends had left his car by the ferry to make it look like he had gone off on the ferry. In fact they had actually killed him and buried his body on the beach at Sanday.
“Indeed the two suspects had driven him in his car, in a duvet in the back, and disposed of his body on the beach.
“We got involved during the search phase. We looked at the soil on his vehicle and were able to identify the area of beach where they had been.
“We compared samples from where his body was found with soil on a shovel belonging to one of the suspects, which he had said he only used to dig in his own garden. We were able to show the sand was nothing to do with the soil in his garden, and was the same as at the grave site.
“His DNA was on the handle, but also within the grave spill. We sieved meticulously through it, and we found flakes of metal that had come off the old shovel – there was a two-way transfer of evidence.”
Mulholland said the Crown Office would continue to work with the soil forensics group on cold cases. One such mystery relates to the 2010 killing of Edinburgh bookkeeper Suzanne Pilley, whose body is yet to be discovered.