Crime Detection. Fingerprinting.

The 21st century has witnessed tremendous change in the field of forensic science including Fingerprinting.

Fingerprints afford an infallible means of personal identification, because the ridge arrangement on every finger of every human being is unique and does not alter with growth or age.

Fingerprints serve to reveal an individual's true identity despite personal denial, assumed names, or changes in personal appearance resulting from age, disease, plastic surgery, or accident.

Fingerprints are classified by the shape and contour of individual pattern, by noting the finger position of the pattern type, and by relative size, determined by counting the ridges in loops and by tracing the ridges in whorls. The information obtained in this way is incorporated in a concise formula, which is the individual's fingerprint classification.

United States recognizes seven different types of patterns, radial loop, double loop, central pocket loop, plain arch, tented arch, plain whorl, and accidental. Whorls are usually circular or spiral in shape. Arches have a mound contour, while tented arches have a spike or steeple appearance in the centre. Loops have concentric hairpin or staple-shaped ridges and are described as radial loops slope toward the little finger side of the hand.

Latent fingerprinting involve locating, preserving, and identifying impression left by a culprit in the course of committing a crime. In latent fingerprints, the ridge structure is reproduced from sweat, oily secretions, or other substances naturally present on the culprit's fingers. Most latent prints are colorless and must therefore be developed, or made visible, before they can be preserved and compared. This is done by brushing them with various gray or black powders containing chalk or lampblack combined with other agents. The latent impressions are preserved as evidence either by photography or by lifting powdered prints on the adhesive surfaces of tape.

Other Fingerprinting techniques include the use of a sound spectrograph--a device that depicts graphically the frequency, duration, and intensity--to produce voice-graphs, or voiceprints, and the use of  DNA fingerprinting, an analysis of those regions of DNA that vary among individuals, to identify physical evidence blood, semen, hair, etc. as belonging to a suspect.

The latter test has been used in paternity testing as well as in forensics.