CRIME A HARD PATH

Evening Star, Issue 23499, 13 February 1940, Page 8

CRIME A HARD PATH

SCIENTIFIC AIDS IN DETECTION VALUE OF ULTRA VIOLET RAYS ILLUMINATING ADDRESS BY DR (TATI ‘ Science aud Science .Detection,’ as -explained by Dr JO. D’Ath to the members of the Dunedin Optimists’ Club (Junior Botarians) at a luncheon today, proved an interesting subject, illustrating some of the many ways m which crime in New Zealand was becoming a path that was increasingly hard to follow. Mr ,C. J.. Darracott was in the chair. ..... Bloodstains provided the initial phase on which Dr D’Ath embarked. Science had reached the stage where bloodstains could be narrowed down either to the fact that they belonged to one given man or did not. It was possible to divide the blood of all persons into four given tvpes. Thus by negative value elimination the fact could be determined! whether certain bloodstains could be attributed to any given man. This was useful in paternity cases. A man could be proved innocent- of a crime by this means, aud lie may be proved guilty, but this was not definite. Bloodstain detection was a sort of negative worki The Hanovia (mercury) lamp, which produced rays outside the range or visibility.—ultra violet rays— was used for the detection of iorgery, The value of ultra violet rays lay in that they showed up things that the naked eya could not see—the rays changed the colours of objects, which led to the discovery of the use of different inks. This lamp was used in the detection or postage stamp crimes, where erasures were shown up vividly, also in cheque forgery in New Zealand. Ultra violet rays were also used to detect blood stains on materials that had been washed apparently clean ot blood stains. They could not be detected by the nak.ed eye. This_ lamp was also used for the classification ot the different types of stain; colours showed out differently under the ultra violet rays. , _ , . . Illegal foods under the Foods Act were sometimes detected by the use or this lamp, especially where adulteration was suspected. Ballistics was becoming "a science m modern times. In Wellington men were employed in this department alone. Crimes committed with guns were becoming increasingly difficult because of the little slips criminals made with their firearms. Bifling made distinguishing markings with the individual firearms, and from examination of the rifling marks on a bullet fired into a body there was much to be determined by the ballistics expert. This was used with great success in the case of the murder of the Sirdar of Egypt, All the Egyptians near the scene of the crime were rounded up, and their firearms examined. There was one found that corresponded with the rifle markings on the bullet in the body. The possessor was arrested, and ultimately confessed. Like fingerprints, no two rifle markings were the same. With shotguns the mark of the hammer-pjn made the distinguishing marks, again like fingerprints, with no two the same. Tt was now possible to . identify any person by the hairs of his head. This was important in cases of “hit-and-run ” motorists. Comparison of hairs on motor cars in such accidents with those of the injured man, made possible a. charge against the motorist. Alibis given by people who had bloodstains on their person, and attributed them to animal stains, were also able to be examined by test substances that could determine the type of blood stainhuman or animal. These substances were costlv, and lasted only six months with effect. They cost about £SO a year in the Dunedin laboratories. In such ways the path of crime was being made much harder to follow Dr D’Ath was accorded a hearty vote of thanks at the conclusion of his ad« dross.