A single firearm particle proves nothing. It’s tiny and could be left on anyone.. it might be a clue but it’s certainly no smoking gun
Scientist on vital questions investigators must ask
Her evidence was crucial in quashing the conviction of Barry George, who was jailed over the murder of Crimewatch presenter Jill Dando.
Now, on the 20th anniversary of the crime, Angela says she still has other misconceptions to quash over the case.
George was convicted of murder in 2001 but it was overturned mainly because of questions over the forensic evidence.
His l aw y e r s bel ieved a single particle of gunshot residue, found in a coat pocket at his property, could have appeared as a result of contamination.
It led to the quashing of the conviction and George, an obsessive celebrity stalker, was acquitted following a retrial.
No other person has ever been charged with the murder and the case has remained shrouded in controversy.
But Angela says the public still have serious misconceptions about how evidence involving tiny amounts of gunshot residues can be given in court.
Angela, 44, who grew up in Kilwinning, Ayrshire, said: “It’s universally agreed that in the UK, the average man in the street has a one in 100 chance of having a particle of gunshot residue on them.
“It is rare, but one in 100 people could pick up a par t icle unknowingly, and the risk increases if you are arrested, go through the custody process or associate with firearms users. This is why we don’t put any evidential weight on a single particle of gunshot residue being found.
“You can’t see a particle of gunshot residue with the naked eye. I say to a jury that it’s like a very fine dust.
“I tel l them a pinhead is one millimetre in size and a gunshot residue particle is one thousandth of a millimetre.
“If you were travelling around on the London underground or on a bus, there are a lot of hobby shooters who might have a particle on them that can be transferred or even armed police officers will travel around using public transport.
“If someone has contact with a pol ic e of f ic er, whether that officer is armed or not, then the likelihood of being contaminated by a particle goes up.
“If a person is taken into police custody, then they might be at a greater risk of being exposed – you have to ask if the custody suite is free from gunshot residue.
“And obviously if you happen to be involved in any sort of armed criminal activity, the odds of you being contaminated with a low-background level of particles increases, too.
“There can be lots of reasons why someone may have a single particle of gunshot residue on them.
“So, whenever ev idence about a single particle of residue is being put to a court then it has to be couched in the correct and balanced way. You have to put caveats on the value of evidence.”
For the last 18 years, Angela,
The grisly side of death is part of this job. Victims of shootings can be young
who studied forensic and analytical chemistry at Strathclyde University, has made a living from her expertise in examining gun shot residues.
Her work has played a role in the conviction of a large number of murderers and other violent criminals.
It has also led to many people who were wrongly accused or convicted of serious and of tencomplex crimes being cleared.
Addressing the Dando case, Angela said: “A disproportionate amount of attention had been placed on the finding of the single particle.
“The key question that hadn’t been asked at the original trial was, ‘ What was the significance of a single particle in a coat pocket found one year after the shooting?’ You had to ask if there was anything in the environment that had led to the particle ending up on the coat pocket.
“I looked at it with a colleague and it all went from there. “It was astounding to us that anyone would think this single particle of gunshot residue could prove anything.”
Despite the high emotions involved in the court cases she assists, Angela only allows herself to focus on the science.
She said: “I’ve worked for both the prosecution and the defence and it doesn’t mat ter who has instructed me. My job is to be an independent and impartial witness.
“My personal opinion about the case has no bearing. You can’t bring your own emotions into it.
“You just have to present your evidence and the judge and jury have to factor that in with all the other evidence of the case.”
Angela says when looking at bullet holes in blood- stained clothing, or examining gunshot wounds in photographs from post-mortems, it can be hard not to think of the victim.
She said: “The grisly side of death is part of this job.
“Often, the victims of shootings can be quite young.
“With the Jill Dando case, it’s still very sad that they haven’t got anyone for the murder.”
Angela has worked on highprofi le cases including the murder of 11-year-old Rhys Jones in Liverpool, the honeymoon killing of bride Anni Dewani in South Africa and the shooting of Glasgow gangster Kevin “Gerbil” Carroll.
While shootings in Scotland are rare, she has followed with interest the search for the killer of Nairn banker Alistair Wilson who, like Dando, was shot dead on his doorstep, in November 2004.
Angela, who set up her own company, Forensic Firearms Consultancy, with gun expert Mark Mastaglio, said: “I’ve not been directly involved in this case but my business partner did some work for the BBC on the type of weapon that was used in the shooting.
“For something like that to have happened in Nairn is astonishing – it’s such a quiet place.”
As well as working across the UK, Angela, who is based in London, regularly advises on criminal cases as far afield as Bermuda and the Turks and Caicos Islands.
And what does she do to get away from the job?
She said: “I do like police dramas.
“Line of Duty is my favourite.”