SCIENCE OF CRIME

Rotorua Morning Post, Volume 2, Issue 586, 18 July 1933, Page 7

SCIENCE OF CRIME

queer gadgets used

MODERN METHODS ADOPTED IN CRIMINAL INVESTIGATION LABORATORIES. UP-TO-DATE ORGANISATION. The crhninal who works alone, aecording to the police, has a much better chance, if he is clever, of avoiding apprehension than the one who operates with confederates. In a criminal group bent 011 thievery, extortion, kidnapping, or any other of the crimes so common to-day, there is al_ ways the possibility that members of the group will quarrel among themselves. The gang, therefore, is only as strong criminally as its weakest member, who often is prone to expose his assoeiates to save himself. Men who make a business of solving erime know the weaknesses of criminals. They also know what to do to make the criminal betray himself in many eases — that is, if there is even the slenderest sort of a clue upon which to begin operations. Police detectives, though in some cases men of limited formal education, understand the criminal mind through a great deal of contact with the underwood. Even by the rough and ready meth'ods of the ordinary police detectives, many crimes are solved with quickness and dispatch. Some crimes, on the other hand, are so baffling that they lie beyond the capabilities of city police departments. It is then that scientific experts are called into aetion. The scientific laboratory for crime detection is a comparatively new thing. In various large cities of late there have been established centres in which physiologists, psychologists, psychiartists, chemists, experts in forensic ballistics, and specialists in other lines are gathered for co-opera_ tion in the solution of puzzling crimes. Such an institution is the Scientific Crime Detection Laboratory of Chicago, which is affiliated with the North-western University and which is under the direction of the law school of the university. This laboratory, besides being engaged actively in the solution of crime, offers a num■ber of courses to* students interested in that line of endeavour. The Scientific Crime Detection Laboratory gives its services free to the police department of Chicago and to other lawenforcing agencies in Cook County, the county in which Chicago is located. For a moderate fee it assists law officers of other parts of the State of Illinois or of other States. What Sherlock Holmes accomplished in fiction a generation ago these modern Sherlocks of crime detection laboratories are accomplishing to-day in fact. They have all sorts of scientific tools and instruments with which to work, strange contraptions undreamt of by the creator of that delightful sleuth of Baker Street. Whereas Holmes had only his test tubes, his band of street Arabs, and his own analytical mind to depend upon in the solving of mysteries, the modern scientific detectives have elaborate, well-equipped laboratories, workshops, specially designed micr'oscopes, prism lamps for chemical analysis, quartz lamps for the study of invisible writing, rifle and pistol ranges and specialised instruments for bullet indentification, equipment for the study and comparison of fingerprints, instruments commonly called lie detector machines for the purpose of trapping suspected criminals through their own lies, and countless other devdces, some simple and others eomplicated for working out answers to crime riddles. Collection of FirearmsThe crime detection laboratory affiliated with North-western University, for instance, has a collection of between 2,500 and 3,000 revolvers and pistols of almost every design and make. Many of the weapons are the personal property of the managing director of the laboratory, an expert in . forensic ballistics, the science of comparison and identification of firearms and bullets. In addition the laboratory possesses cartridges to fit its many weapons. Through the use of an optical instrument known as a bullet comparison microscope, experts in forensic ballistics can compare a bullet used in a crime with test bullets fired by a number of weapons, and, they say, positively identify the weapons from which the bullet employed in the .crime was fired, provided they have been able to obtain possession of that weapon. Though pistols, revolvers and rdfles of the same make and the same model may appear identical to the naked eye, there are minute differences in the machining of the rifling of the barrels and the firing pins that are brought out in microscopic examination. The

bullet comparison mdcroscope gives the operator of the instrument a view of the crime bullet, often a fatal bullet, and a test bullet at the same time. That is, half of th'e crime bullet meets half of the test bullet in the eyepiece of the microscope. If the microscopic lines of the two bullets meet and fit exactly, the identification of the weapons is establdshed. But bullet and weapons identification is only a very small part of the work of a crime detection laboratory. Finger print identification is another important department. Though virtually every up-to-date police organisation has a finger print bureau for the identification of criminals, the scientific detectives have borrowed and improved on the idea and made good use of it. Handwriting Experts. Every effteient crime detecting laboratory has on dts staff at least one expert in handwriting, a person capable of tracing the authorship of a letter of a forged paper, no matter to what extremes the writer weixt to disguise his writing. Type-written letters also can be used as clues in crimes, there being experts in this line who can tell the differences in papers written on different typewriters, even though the typewriters are of the same make *and the same model. No two typewriters align their various letters exactly alikei In Fringing out invisible writing be-

tween the lines of a seemangly innocent letter, scientific detectives resort to the ultra-violet lamp, which makes characters produced by such' fluids as lemon juice, aspirin solution, or coffee fluoresce in its light. Criminals in priisons often communicate with xriends on the outside by using socalled invisible ink, which is made visiible temporarily by the application of heat. The lie detector has been brcught to the fore in recent years in the .detection of crime. Though its findings are not accepted as evidence in Court, the machine has proved a great aid in isolating suspected persons from innocent persons and in obtaining confessions from culprits. The lie detector registers upon a moving roll of paper the variation in the blood pressure of the person being examined, the increase in the strength of the pulse or heart beat, and the fluctuations in respiration. A guilty person being questioned wh'ile undergoing a lie detector test, in a majority of cases, according to the scientific detectives, will betray his false-» hoods on the graph of the machine, no matter how great an effort he makes to remain cairn.