DUBAI // It was a routine crime: a young woman was standing in the foyer of a building in Dubai when a man came up behind her, grabbed her purse and fled.
When the victim reported the crime to the police, she may have doubted she would get anything more than a crime reference number.
There were no clear clues to the perpetrator – even the security cameras had failed to register his face. But they did record that he had walked barefoot to the crime scene and had a distinct, flat-footed gait.
It was enough for analysts at Dubai’s General Department of Forensic Evidence and Criminology to create a three-dimensional picture of how the man walked. When a suspect was arrested, comparison with the imagery revealed a match.
Forensic kinesiology, the study of the mechanics of body movements, is one of a host of techniques detectives in the UAE use in solving crimes.
As the international forensic science conference that opens in Dubai today shows, it is a resource that continues to grow.
Those attending will learn of advances such as a voice recognition software that reveals tell-tale signs of stress in the voice of fraudsters and new forms of pattern analysis for detecting fraudulent signatures.
DNA profiling – the gold standard in forensic evidence for more than 30 years – is also becoming more powerful.
Researchers at Khalifa University and Abu Dhabi Police have identified tell-tale markers in DNA related specifically to Emiratis. This will help detectives to narrow down the ethnicity of perpetrators.
Meanwhile, the vulnerability of DNA exposed to the elements is being circumvented by a new technique using proteins that are found in hair strands.
Researchers in the US have shown that the 300-plus proteins on a single strand of hair can reveal the identity of centuries-old archaeological specimens.
Reporting their findings in the scientific journal Plos One, the researchers emphasised that while promising, the hair protein analysis is still in its infancy.
The technique needs to be fully understood and its accuracy demonstrated before it is routinely used in police work.
That seems entirely reasonable – yet despite being a discipline whose reliability can be a matter of life or death, such caveats have been the exception rather than the rule in forensic science.
Since the advent of fingerprint identification more than a century ago, the scientific basis of many widely used forensic techniques has remained worryingly flaky. The trust put in fingerprint identification was long based on little more than the idea that so intricate a pattern could not be replicated in every detail.
In the 1890s, the eminent Victorian statistician Sir Francis Galton guesstimated the chances of two fingerprints looking the same was about 1 in 64 billion. Arguing that this was far more than the population of the world, he concluded they were effectively unique. Despite being based on fewer than 100 samples and questionable logic, the idea of identifying criminals by a fingerprint proved so alluring that by the 1920s standard texts simply took the uniqueness to be an undeniable fact.
The same cavalier attitude has since been applied to many other forensic “breakthroughs”, from the lie detector to fabric matching and soil analysis.
Despite being used in countless cases the reliability of such techniques has rarely been scientifically assessed, and when it has, the findings have rarely engendered confidence.
In 1975, three men were convicted of being part of a gang that murdered 21 people in the IRA pub bombings in Birmingham, England. Their guilt seemed to have been put beyond doubt by a chemical test said to prove contact with explosives.
However, in the mid-1980s the UK government forensic service carried out a reliability check of the chemical test, which revealed that while it gave positive results if exposed to chemicals linked to explosives, it did the same in response to traces of urine or even the surface of playing cards. The three men convicted were acquitted.
In 2009, forensic science ended up in the court of scientific credibility, with the case for the prosecution led by the prestigious US National Academy of Science, which was blunt in its assessment.
“The simple reality is that the interpretation of forensic evidence is not always based on scientific studies to determine its validity, this is a serious problem,” it said.
This week’s conference includes a session on a forensic technique about which the academy was especially scathing: bite-mark identification.
The idea that teeth leave unique and reliable bite patterns on skin came to prominence in the 1979 trial of the US serial killer Ted Bundy. Wounds found on the body of one of his victims were said to be consistent with Bundy’s dental pattern and played a key role in his conviction.
Since then, bite-mark analysis has been used in many trials – despite the academy’s report in 2009 concluding that there is “no evidence of an existing scientific basis” to the claims made for it.
No one knows this better than Keith Allen Harward, who was released last year after spending 33 years in prison for a rape and murder he did not commit.
He had been convicted on the basis of testimony by no fewer than six “forensic dentistry” experts, who claimed bites on the victim were consistent with Harward’s dental records.
His innocence was revealed by DNA evidence obtained by the Innocence Project, set up in 1992 at the Cardozo School of Law in New York to re-examine miscarriages of justice.
In 2013, a man in California was held on suspicion of murder for four months after his DNA was found on the body of the victim. Investigators later found that the man had been in hospital and treated by a paramedic who later went to the crime scene – and accidentally transferred his DNA.
If miscarriages of justice are to be avoided, forensic techniques must all stand trial in the court of science.
Robert Matthews is visiting professor of science at Aston University, Birmingham, UK
