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Forensic

The corpse is a silent witness who never lies - Anonymous

Forensic

image by: West Midlands Police

"In the search for justice is the age of the great detective over and are we now living in the era of the scientist? A new book reveals all...

YOUR average criminal today knows how to handle even the cleverest questioning. Most will say nothing at all until their lawyers are present. The expression "no comment" has become commonplace. And eyewitness evidence has become less reliable, as defence teams become more adept at casting doubt upon it.

The fact is that most major cases today are closed by the use of forensic science, through the detailed attention of the people in white coats. Science has become the final adjudicator.

It wasn't until towards the end of the 19th century that the authorities began to take a scientific approach to identifying criminals and keeping proper records. Prior to that a man wanted for a violent robbery in, say, Nottingham might be arrested in London for being drunk and disorderly but if he gave a different name he could pass through the hands of the police without them ever realising who they had in custody.

It was a Frenchman Alphonse Bertillon who finally addressed this problem. He was working as a clerk for the prefecture of police in Paris and realised that the methods of identification being used were essentially worthless. He began working on his own ideas.

His first innovation was to cut photographs of various faces into strips so that their features could be rearranged to form new faces. Witnesses could use these to construct an approximate image of a criminal they had seen. Bertillon had invented the first of what we would now call photofit pictures.

But his greatest breakthrough came when he began to record people's measurements. He decided to take 11 different measurements from each subject, including their height, the length of their arms and legs and the size of their feet. Like every Parisian tailor Bertillon knew that nobody had exactly the same measurements as anybody else.

Bertillon was sure that using his system he could identify anyone, living or dead, who had previously been measured. There was opposition to his idea. Many - including famous French detective Gustave Mace - thought it was a waste of time and money. But eventually in 1882 Bertillon was given three months to trial his methods.

At first he had little success: although he had taken the measurements of many criminals he had been unable to use his records to identify a single reoffender. But two weeks before the trial period was due to end his luck changed.

A criminal who had given his name as Dupont was brought in. Bertillon took his measurements and then went to consult his files. To his delight he found a match, not for a man called Dupont but for one called Martin who had been arrested a couple of months earlier for theft. Faced with this evidence "Dupont" confessed he really was Martin - he had given a false name in the hope of being given a lighter sentence as a first time offender.

It was a triumph for Bertillon's system, which was soon adopted across Europe. So why don't we all know about his measuring innovation? Because it was replaced by a simpler and more brilliant method.

Fingerprints have been used as far back as 300AD. It wasn't until towards the end of the 19th century that the authorities began to take a scientific approach to identifying criminals and keeping proper records

Each of us has a unique set of patterns on the tips of our fingers. As far back as 300AD we find a handprint being used as evidence in a case of theft in China. But creating a workable system for fingerprints to be categorised so that they could be used by the authorities proved to be difficult at first.

It was Francis Galton, cousin of Charles Darwin, who solved the problem. Building on the work of two other fingerprinting pioneers Henry Faulds and William Herschel he set about creating the simplest possible system of classification. He focused on the triangular shapes formed where ridges on the fingertips come together, known as the deltas.

Galton published his findings in 1891, crediting Herschel's help in his work but not Faulds. Galton's system was soon taken up by the British authorities and fingerprints remain a key part of criminal inve tigations today.

Apart from being quicker than taking 11 measurements from a suspect, the huge advantage of fi gerprinting is that a criminal may accidentally leave their prints on objects or surfaces at a crime scene. If such prints are found they are an indisputable way of proving that a person was there.

But the greatest breakthrough of all in forensic science didn't come until the end of the 20th century. And the circumstances in which it was first used to catch a violent criminal were incredibly dramatic.

On September 10, 1984, Dr Alec Jeffreys of the University of Leicester observed during an experiment that the DNA from members of the same family shows many similarities but also significant differences. He quickly grasped what this meant: that we all have a DNA "fingerprint". Any person can be identified by their own unique genetic code.

Quite remarkably the first place this advance was to be tested in a criminal investigation was in Leicestershire itself. On November 22, 1983, in the village of Narborough a schoolgirl called Lynda Mann was found dead. She had been sexually assaulted and strangled. Despite the best efforts of the Leicestershire Constabulary Lynda's killer was never found and the inquiry was finally run down.

Tragically this wasn't to be the end of the story. On August 2, 1986, the body of 15 year old Dawn Ash worth was found near the village of Enderby, not far from Narborough. She too had been sexually assaulted and strangled. This time the police found a suspect: a young lad who worked nearby as a hospital porter. After seven hours of questioning he broke down and confessed. They had their man.

But the police wanted to prove his guilt beyond doubt and to link him to the death of Lynda Mann. They therefore approached Dr Jeffreys, giving him DNA samples taken from the bodies of both girls to analyse. He was able to tell them one thing that they wanted to hear and one that they absolutely didn't. The DNA evidence proved that the same man had killed both girls. But it was not the man they had in custody.

Shamefaced, the police adopted a radical approach and decided to take blood samples from every male in the district. It was an enor mous job but they knew they had to find the killer. However even after taking blood from thousands of men they had no match. Then it came to their attention that a man called Ian Kelly had been telling people that he had given blood on behalf of a friend by the name of Colin Pitchfork.

It soon became clear why Pitchfork had persuaded his friend to stand in for him: when he was arrested on September 19, 1987, his DNA was a perfect match. The following year he was tried and convicted for the double murder.

Today the tiniest spots of blood or stray hairs left at a scene can be used as DNA evidence. Genetic fingerprinting has come into its own. There are many other fascinating areas of forensic science, such as microscopic analysis of clothing fibres, poison detection or the matching of bullets to the gun that fired them.

So the game continues, science against the criminals. And science must always fight to remain ahead."

Source: Nigel McCrery, How science is helping us solve some of the world's most notorious crimes...Express, September 30, 2013.


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