THE latest talk was given by Mike White, a Scenes of Crime Officer with West Mercia Police.

His job is to gather evidence that will subsequently be examined as part of the process of identifying the criminal.

Although fingerprint identification is an old technique, it is still an important element in detection. In 1823, it was discovered that each person's fingerprints were unique to them, due to varying amniotic pressures in the womb prior to birth.

The first successful prosecution using fingerprint evidence was in 1892.

Although prints are clearly visible on substances such as paint or blood, they can be obtained from surfaces by dusting on powder with special glass-fibre brushes.

The condition of the samples will often vary but there are several techniques for enhancing their quality. For recognition purposes, the lines on fingerprints are divided into arches, loops and whorls. As a safeguard against error, fingerprint comparisons are subject to a triple check and must have 16 similar points for verification.

Footwear prints provide another means of identification. The type of sole, signs of wear, or substances adhering to them provide clues.

Car tyres also provide information.

The greatest advance in forensic science is the use of DNA. Skin, blood, saliva and cigarette ends are just a few of the sources but the risk of contamination has to be considered.

Other aspects of forensic science include bloodstains, which according to their pattern may reveal the nature of an attack. Again there needs to be caution as the assailant may also cut himself or herself accidentally.

The remains of a shooting incident may reveal the direction and distance the bullet travelled and bullets can often be matched with a particular weapon by noting distinguishing marks on both of them.

Debris scattered around an incident can often provide further details, particularly if it reveals identifiable origins.