THE COLD CASE CRACKER
In 40 years of crimefighting, Tom Nelson has seen a revolution in forensics – but even now, old-school skills still help nail crooks who think they’ve escaped justice...
scene. Sinclair, who died in March aged 73, had been ordered to serve a minimum of 37 years in 2014 after a jury found him guilty of the girls’ murders, as his DNA was also found at the scene.
Mr Nelson says that in another case where someone tried to cover up a murder by putting up fresh wallpaper, it was stripped off and ‘we were able to go behind the wallpaper and find some [genetic] material on the inner surfaces’.
Around 20 cold cases are being examined in Scotland at any one time. For Mr Nelson, older cases ‘really prove that not everyone is going to get away with things and that science can be used going back a number of years’.
Taking a personal interest in any case is ‘discouraged’ among his scientists, as he says all his staff know they are ‘servants of the Crown’ – becoming too involved could lead to a less objective approach.
‘I would rather they left it up to the court,’ Mr Nelson says. ‘You give the best evidence you can give: if you lose that, you lose everything.’
Jurors are arguably more knowledgeable about forensics than ever before because of television shows including Silent Witness or podcasts such as Evil Has A Name, which tells the story of the hunt for the Golden State Killer.
‘I don’t watch any programmes like that because I just get frustrated, to be totally honest,’ Mr Nelson says.
‘Sometimes they increase expectations of the science and that’s one thing we try to train our staff – whenever you’re in the witness box, you really have to explain what you’re doing in the simplest of ways.’
THE experts’ role is to help interpret evidence as well as presenting it to jurors, some of whom he says may have been ‘waylaid by Google’ – picking up faulty information about forensics online.
Mr Nelson adds: ‘With a lot of the evidence we provide today, it’s not necessarily the science that’s questioned – it’s what does it mean?
‘If I find DNA or a fingerprint on a drugs wrap – what does that mean? Did that person have access to that or handle that?
‘Someone broke into a house and you find DNA or a fingerprint on a window – what does that mean? Does that mean that person could have got into that house?
‘Or were they the window cleaner (obviously they weren’t cleaning them very well if the fingerprint was still there) a couple of days beforehand?’
Mr Nelson, who has three grownup children, began his career in Northern Ireland, where he developed a specialism in fire investigation and chemical analysis, before moving to Scotland in 1995 as boss of the forensics lab in the Lothian and Borders Police area.
Today, his team are working on the ongoing investigation into the fire which engulfed the Glasgow School of Art last year, involving the removal of 400 tons of debris.
He has also advised the Metropolitan Police in London on the probe into the Grenfell Tower fire in 2017.
His department’s workload is about to soar further with the planned introduction of drug-driving laws in Scotland this year – meaning samples taken from motorists suspected of getting behind the wheel after taking illicit substances will have to be analysed.
‘You are talking about many, many hundreds of samples coming in,’ Mr Nelson says. ‘You don’t know until you start.’
As for criminal investigation, he boldly predicts developments in forensic science will effectively put an end to the possibility of anyone getting away from a crime scene without inadvertently leaving behind some evidence that they were there.
‘Every contact leaves a trace,’ he says. ‘It doesn’t matter whether we can detect it today or tomorrow – you will always leave something at the crime scene.’
Mr Nelson has a final stark warning for anyone who believes they can commit the perfect crime. ‘I believe some people may think they’ve got away with things today,’ he says. ‘But actually, in five or ten years’ time, they might have that knock on the door.’