DEVELOPMENTS IN FORENSIC IDENTIFICATION AND ITS CONTRIBUTION TO CRIME PREVENTION
Ch. Supt. Pinchas Bergman,
Division of Identification and Forensic Science,
Israel National Police
The investigation process, including its components such as criminal identification, is not usually considered to be a factor in crime prevention since, after all, it takes place ‘after the event’. However, there is no doubt that a high rate of crime-solving, arrest and conviction is a strong deterrent of potential crime and, as such, a real contributor to crime prevention.
The four contributions of forensic science and identification to crime prevention are:
* It can identify the offender without any investigative intervention whatever and thus raise the clearance rate;
* Linking an offender to the crime-scene by physical evidence increases the likelihood of getting a courtroom conviction;
* Suspects faced with material, physical evidence linking them to the crime will frequently admit defeat and confess, even to previous, hither-to unsolved, crimes committed by them;
* Judicial sentences tend to be heavier when the convicting evidence is material and scientifically established. Thus, the criminal remains behind bars, unable to commit crimes, for longer periods of time.
We present here the most important of recent innovations:
Lifting and Matching/Identifying Fingerprints
The advances in this field have been of great practical benefit to investigators and have raised the case clearance rate significantly.
Lifting Fingerprints: A range of new techniques and materials now permits the lifting of finger prints in what used to be considered impossible situations from certain materials e.g. types of plastic, from damp or bloody surfaces, or after a long lapse of time. These methods include advanced chemical and physical techniques chemical reagents that augment the contrast between the print and the background surface, powerful light sources (laser and others) of visible and ultra-violet light which bring up latent prints, coating prints with metal vapors and deposits of metal solvents, etc.
Matching Prints: In this field, the installation of the automated and computerized AFIS system has caused a veritable revolution in the ability to match a print lifted from a crime-scene with the INP’s print bank. The AFIS can make a match within minutes, no matter how long before the offenders’ prints were taken. This process requires no investigative input other than locating the print at the crime-scene and the subsequent arrest of the suspect.
Identifying Persons by their DNA Profile (Genetic ‘Fingerprint’)
No less dramatic have been the advances in biological identification methods. If before, biological tests could place a person in a certain sub-group (by blood type, blood components, etc.) now it can make individual or almost individual identifications. In practical terms this means that the identification by DNA from a sample of biological material
(flesh, blood, saliva, semen, etc.) is frequently certain.
Using these methods, one can even set up databases of genetic profiles of convicted criminals. Such a database would, for instance, identify a recidivist rapist by the seminal fluid he leaves at his new offense.
DNA replication by the PCR method means that high quality identifications can be made from the tiniest quantities of biological material. This methods is also quicker than others and will probably become the standard method of biological identification.
Field Testing at the Crime-Scene
A whole new range of methods are available now for conducting tests at the crime-scene itself, close in time to the commission of the offense:
* Field kits for the rapid, preliminary identification of drugs, explosives, traces on human hands of having handled metal (steel)
objects in general and firearms in particular, bullet holes, etc. * Chemical techniques for lifting latent shoeprints and a range of methods for copying shoeprints.
* Methods for collecting microscopic particles (gunshot residues) from the bodies and belongings of suspects and for the covert marking of objects with luminous substances.
Assessment of polygraph tests is now being computerized. The first stage is to computerize the test record, its storage, retrieval and transfer. The planned next stage is a large-scale operation to computerize the testing itself and the analysis of the record.
Mug-Shot Album, Identikits, Identity Parades
* A number of methods are being evaluated for arranging the photos in the mug-shot album by similarities of feature, so that the process of riffling through the album to get at the target photo can be speeded up.
* A number of methods are being evaluated for composing identikit pictures, among them computerized methods.
* The methods of holding identity parades are being re-evaluated, with all their advantages and disadvantages, with the aim of consolidating their evidential value.
Other Examples of Computerization
* Computerization of tool-marks: it is possible to connect two offenses committed with the same implement (housebreaking tool, firearm) by the microscopic traces the implement leaves on objects on which it has been used. Computerization will make it possible to build up an operational database of such markings for future identifications.
* Developments in the computerization of the Mug-Shot Album will permit rapid transmission of photos from one police station to another by computer communications networks and will be of great help to investigations.
* Computerization of lost and stolen property and the compiling of a databank will permit the rapid identification of objects found or seized during the investigation of property crime.
(See also the article in this Report on computerization within the INP.)
The advances in forensic identification methods are making a very cost-effective contribution to crime solving and crime prevention. They make more likely the conviction and incarceration of serious offenders, which, in turn, deters others from following in their footsteps.