The use of photography in police work dates from 1852, when the Swiss Federal Government authorized the Department of Justice and Police to have photographs taken of all vagrant beggars found in cantons other than their own.
In December 1854 the governor of Bristol Gaol, England, issued a circular recommending other prison governors to follow his practice of having a photograph taken of every prisoner in his charge. The same year, a "wanted persons" notice with photograph, made according to the' suggestion of Moreau Christophe, was billposted publicly in France. This was first done in England in 1861. It was not until 1870 that the photographing of every prisoner in England and Wales was made compulsory. The procedure was justified during the year 1871-72 when 375 arrests were made in consequence of the criminals having been identified by photographs.
Today the more advanced photographic techniques are in constant and daily use by all the larger police forces of the world.
Well equipped photographic departments are an integral part of police administration and their contribution, especially in crime detection, is an important one.
Great reliance is placed upon photographic evidence by the Courts of this land and hardly a major crime of any importance is solved without photographic evidence of some kind.
Evidence of this type is factual, objective and without bias. For recording the scenes of serious crimes its value is inestimable.
The photographing of scenes of crime follows well defined practice. The locus is recorded exactly as found and before anything is touched or disturbed. Nothing is moved before complete photographic coverage has been made from several angles to meet all eventualities. If bodies, articles, etc, have been moved they are never replaced in an attempt to approximate their original position. This amounts to reconstruction and reconstructed photographs of scenes of crime are not admissible as evidence in most Courts of Law. Any clues present, such as shoe prints, finger prints, bullet marks, scratches, signs of entry and egress, etc., are recorded with due regard to their relation to each other. Articles bearing on the crime, such as weapons or tools, are photographed in their exact position before removal for examination and further photography.
Wounds on bodies are always photographed as it is possible from a study of the photograph to deduce with a high degree of accuracy the shape and size of the weapon used. Tattoo marks and prominent scars are also photographed in every instance where identification is in doubt.
In recording these scenes of crime the aim is to produce a series of photographs which will tell the story of the crime. All prints must carry a good range of tones and be absolutely sharp from back to front.
Equipment for this type of work can be any good stand camera from quarter to half plate size. It should have a full range of camera movements and be fitted with a double extension.
Wide angle lenses are extremely useful on occasions if used with due regard to the risk of distortion. The resultant enlargements up to 10 x 12 inches, a convenient size for presentation in Court, should be indistinguishable from contact prints.
Lighting for interior scenes of crime will vary, but the majority of cases can be covered with expendable flash bulbs. "Painting" the scene with portable half watt lighting is sometimes useful. Electronic flash. owing to the comparative low light output from the portable types, is hardly suitable where large areas have to be covered sharply and well lighted from front to back.
With many offenses a photograph is the only way in which the evidence can be presented to the Courts to supplement the opinion and explanation of the expert. In cases of fingerprint evidence, for instance, the similarity of the prints is quite easily followed by means of the photograph.
Ballistic evidence, sometimes of a highly technical nature, is made quite clear through photography and in forgery cases the expert's evidence on handwriting is always supported by means of the photograph.
Comparison photographs, which involve photography of the "trace" found at the scene of a crime, with a known standard are frequently used by the police. Boot and shoe impressions found at scenes of crime can readily be compared with the suspect's footwear, marks made by jemmies and tools can be photographed same-size and the instrument "offered up" to the photograph.
Photographs of the criminal aid the investigating officer in his hunt for the criminal. A true likeness is required as opposed to a portrait. Pin sharpness is essential, and under no circumstances must there be any retouching. All facial blemishes, marks and scars must be clearly delineated. Profile and full face photographs are made at full length to 1/27th scale. Special apparatus is available where large numbers have to be dealt with, but police photographers usually make use of a special back fitted on to a half plate camera which will accommodate the regulation photograph. Operating indoors under controlled lighting conditions and using time and temperature technique for processing ensures a uniform standard of print.
Document reproduction is carried out on a large scale in cases of fraud and processes such as photostat, dyeline reflex printing and Autopos are commonly used.
The examination and photography of questioned documents form a large part of police photographic work and the special properties of the invisible light rays at both ends of the visible spectrum are utilized.
Ultra-violet rays are turned to good account in a number of ways in police investigation. They are used in all cases in the preliminary examination of documents where forgery is suspected. The eradication of original written matter if effected by chemical agency and its substitution by other writing, can generally be detected; any application of chemicals to paper can nearly always be revealed because the area so treated gives off a totally different fluorescence from the remaining part of the document. Usually the original writing is disclosed and when photographed provides irrefutable evidence of forgery.
"Secret" writing with so called invisible inks or urine, milk, onion juice, etc, all give a characteristic fluorescence and are generally detectable with ultra-violet light. Oil and grease stains give off a particularly brilliant fluorescence and are easily recorded.
Blood stains on garments which have been washed to remove the stain can be photographed in U.V. light. Invisible laundry marks which fluoresce strongly under U.V. light are sometimes found on articles of clothing left at scenes of crime and afford valuable evidence when photographed and produced in Court.
The powers of penetration of infra-red rays are used in a variety of ways in police photography. Where written matter is obscured by other writing, scribble, dirt, oil, etc, infra-red photography will give a good recording within certain limits. Partially burnt and charred documents can be photographed with a fair degree of success. Faint pencil writing due to age, wear, or dirt can be "boosted" and rendered legible. Old scars and scarcely visible tattoo marks on bodies can be revealed by infra-red photography. These rays can also be used to determine the distance at which a firearm is discharged from the victim. Powder staining, invisible on dark garments, can be seen quite plainly on the photograph. This evidence is often of great value.
Cine photography is used in police work mainly in recording traffic and crowd control. It has been used on a few occasions to catch the criminal in flagrante delicto, but these opportunities, as can be well imagined, are rare.
Instructional films for the training of police are made but film strips are to be preferred for this purpose, and are used extensively.
Color photography, with its well known limitations as regards fidelity in the print, has yet to prove its worth. Color transparencies, however, are being used on an ever increasing scale and have provided evidence on many occasions.