TRACKING OF CRIMINALS

Hawke's Bay Tribune, Volume XXI, Issue 304, 8 December 1931, Page 11

TRACKING OF CRIMINALS

USE OF UNSEEN RAYS. WITCHERY OF “BLACK LIGHT.’’ The newest thing in criminal hunting it the use of rays. In New York and Chicago X-rays, piercing through solids to find hidden clues; strange, “oneplane” polarised light, making possible a startling new method of tracing dust and minerals; mysterious ultra-violet “black light,” ferreting out evidence through the sheen and glow of common minerals, are now major allies of the law. In other centres also scientifically trained detectives are using these little understood vibrations of the ether to solve baffling crimes. All of these rays are formed by electro-magnetic vibrations and differ only in wave length. _ Polarised visible light, the only one of the three seen by human eyes, has the longest wave length; X-rays has the shortest, with ultra-violet falling between. In the whole world there are to-day less than half a hundred detectives trained to capture criminals with those new weapons. Yet, to-morrow, ray-using “Sherloeks” will be a part of the detective systems throughout the world. “Already a list of their achievements reads like a page from some scientific Arabian Nights,” states Mr. Edwin W. Teale in Popular Science. He instances the solution of the Bandana Murder Case, in America, not long ago. Motorists, stopping to change a tyre on a side road, discovered a body lying in the ditch, a bullet through the head. There were signs of a struggle, and a single clue, a red bandana handkerchief caught on bushes through which the slayer had escaped. The victim proved to be a miserly rich mail who was foreclosing on farms in the neighbourhood. He had many enemies. Threats had been made against him. All those who might have had cause for committing the murder were held on suspicion. In the meantime, the handkereheif, into which grayish lines of dust had been caked by perspiration, moved to the centre of the stage. The intelligent chief of police, realising that the reputation of many men were at stake, took -extra precautions and rushed the bandana to aftother city for examination by an expert. He followed this expert to his laboratory, watched him slip the cloth under an ultra violet lamp and switch on the rays. Then the amazed officer saw the dust burst into lines of indigo fire. Watching the intense, vivid blue for a moment, the expert turned to him with a single word: “Feldspar.” Samples of dust from the farms of suspected men were next placed under the rays. They glowed in various hues, most of them showing the presence of feldspar, but none reacting to the light with the exact shade of the bandana particles. Not far from the scene of the murder there was a large clay pit from which labourers dug material for a pottery factory. Samples of this clay were placed under the light and burst into the exact sheen of the original dust. A speedy round-up of the workers resulted in the capture of the culprit. He had shot his victim during a struggle in an attempted hold-up. As he fled from the scene, the bushes tore the bandana mask from his face and this square of cloth, by the witchery of “black light,” became the drailitie witness that convicted him and freed a number of innocent men.