Experts

By J. Morton. 2004

It is amazing to consider just how the concept of the expert witness has influenced criminal—and indeed civil—trials over the years. Cot death cases and those where children have been wrongly taken into care are some of the more recent examples. Of course, there have always been doctors around to give medical evidence, but in roughly the last 100 years a profusion of experts have come and gone in such fields as fingerprinting, handwriting, ballistics, offender profiling, hypnosis, DNA and a host of others. In cases of proven charlatans or simply the inexpert, trails of destruction have been left behind. And, even in cases where the best of the experts are witnesses, their evidence has quite often been found to be hopelessly wrong. The jury usually gets the blame for reaching an incorrect verdict based on this evidence, but perhaps the blame should be more widely shared. For far too long judges have given too much weight to the evidence of the prosecution’s expert witness, who turns up to say he has had 14 years’ experience examining fingerprints and therefore cannot possibly be wrong. It took a considerable time before fingerprinting superseded the measuring of the criminal developed by Alphonse Bertillon in the 1880s. In essence, however, both methods relied on the same thought process as that used for DNA evidence. Bertillon developed a system which identified criminals whose noses, ears, eyes and so forth matched those on cards he had kept of other earlier measurements. If two persons had the same height the chance was 4 to 1 that they were the same people; if a second measurement matched the chance decreased to 16 to 1 whilst if 11 other measurements matched the mathematical probability was a staggering 4,191,304 to 1. It is the same with fingerprints whorls and DNA—we are asked to accept that the chance of it being someone else is so outlandish that the man or woman in the dock must be the same as the one who left the print or the sample. Bertillon’s system eventually lost out to the fingerprinting method, which had been used for centuries in the Far East. The serious problem had been that it was very difficult to classify and index the prints and it was not until the 1890s that a satisfactory method was worked out. The first murder case in Britain that relied to a great extent on fingerprinting was that of the Stratton brothers who murdered a shopkeeper and his wife in 1905. The apotheosis of the fingerprint came when a child was murdered in a Blackburn hospital and a single fingerprint was taken from a bottle of water. All the males in the town were invited to give samples of their fingerprints and finally a man was identified. Since it is generally accepted that whatever is done to them, fingerprints do not change, but simply grow back to their original pattern, there have been repeated calls for the fingerprinting of every man, woman and child.