Fingerprint Sections in Auckland, Hamilton, Wellington and Christchurch identify latent fingerprints and examine crime scenes and exhibits for fingerprints.

The National Fingerprint Section in Wellington maintains storage of more than 430,000 original sets of fingerprints, and manages the Automated Fingerprint Identification System computer system.

About fingerprints

Fingerprints are designed to increase the frictional ability of the skin. A fingerprint consists of raised areas called ridges. It is these ridges that, when they come into contact with a receptive surface, leave an impression called a fingerprint.

The qualities of this skin means that it is found on the palms of the hands, fingertips and the soles of the feet. These are areas where increased friction is advantageous for gripping, walking, swinging etc.

The sweat glands that supply the skin with moisture have an opening on the apex of the ridge. The sweat flows out of this pore and along the tops of the ridges. When somebody touches a surface the sweat is transferred to it in the pattern of the fingerprint.

A fingerprint can also be left with a substance contaminating the fingerprint such as ink or grease. A three dimensional impression may be left of the finger pattern if the surface handled is soft, such as wax or putty.

Because fingerprints are unique and permanent, they make an ideal way to identify individual people. The identification of individuals involves the comparison of one fingerprint, from an unknown source and comparing it to a fingerprint from a known source. The characteristics are compared until a sufficient number are in agreement for the analyst to be satisfied that they are from the same source.

Fingerprints are a common tool for use in the solving of crime. This evidence can be used to identify persons present at the scene of an offence and thereby locate unknown offenders, corroborate a persons story and confirm the actions of an offender and/or victim. Fingerprints can be used to identify bodies and find the correct identity of arrested persons.

Pattern types and characteristics

All fingerprints can be classified into three distinct patterns:

Within the fingerprint patterns there are numerous characteristics present:

The uniqueness of a fingerprint comes from these characteristics differing in the way they are orientated, positioned and their relationship to other characteristics.

Biological principles

Fingerprints follow three basic biological principles:

Pattern type: All fingerprints can be classified into pattern types.

Uniqueness: Each fingerprint is unique, no two people have the same fingerprints. Each person's fingerprints differ from finger to finger. For example your right thumb will have a different characteristic orientation, position and relationship to the right forefinger.

Permanence: Fingerprints are unchanging from 3 months feotal life until decomposition. Scars are the only exception to this rule, these then become permanent themselves.