Criminals beware! A single hair found at a crime scene can now provide investigators with an instant lead, thanks to a new database of human scalp hair characteristics developed by scientists in Australia.

A team at the Queensland University of Technology, led by Paul Barton, analysed donated scalp hair from 70 people of each gender and a variety of ages from African, Caucasian and Asian backgrounds using infra-red radiation instruments and interpreted the results with the aid of mathematical methods.

"I analysed scalp hair fibres using novel approach for hair analysis in the forensic context to look at structural chemistry of each fibre.

"By recording patterns of the structure of the keratin protein in the hair I was able to build forensic profiles of the donors which could be discriminated on the basis of gender, ethnicity and hair treatment.

"We found, for example, that women's hair has slightly different protein structure, and they exhibit more of certain amino acids. When people bleach their hair they destroy the melanin pigment, and also as a side effect it can break down amino acid cystine and other bonding mechanisms responsible for stable protein structure of the hair.

"The decrease in cystine tells us whether the hair came from someone who has had hair bleached or permanently dyed. It means investigators can instantly get information from a single hair at the crime scene that they didn't have available to them before with the aid of portable infrared radiation instrumentation," Barton said. .

According to the scientists, the new method was fast and complemented the other methods used for analysing hair -- microscopy which can tell the colour, diameter and type of body hair, and DNA analysis, which is most useful only when the hair root is still attached.

"The database developed could be further refined with the analysis of hair from more people. I would like to add a fourth level of analysis and be able to delineate the ethnic background information into different nationalities," he said.

The scientists hope to take this project to the next stage of application with potential users of the technique, such as crime investigators.