Finding evidence at a scene is crucial to solving a crime, and more frequently the use of DNA analysis plays an important role.

But, scientists say, it is not as easy or as quick to analyze DNA samples as it looks on television. For instance, scientists say that in order to track DNA through a hair sample, several conditions must be met, including having a fully intact hair to retrieve data.

But the process may be helped tremendously by a new technique of analyzing the surface of a hair under a special microscope. This is important, particularly if a criminal  has disguised himself or herself with the use of hair dye.

Two scientists at Northwestern University say they can not only analyze the hair strand more quickly and more precisely through Raman Spectroscopy, but they can also pinpoint even the dye's brand.

Raman spectroscopy is used in chemistry and is a technique that uses the scattering of laser light to track energy of substances and particles. In the case of a hair strand, the technique can determine data related to any chemical or substances on the hair.

Dmitry Kurouski and Richard Van Duyne released their findings in a report that appears in the American Chemical Society journal Analytical Chemistry.

The researchers said in their report that typical crime-scene investigations that include the use of a victim's or perpetrator's hair can be stymied by insufficient comparison evidence. The typical investigations are based on comparing two strands of hair and sometimes there is lack of evidence.

The research was prompted by the need for more accurate investigative technique, and Kurouski and Van Duyne proceeded with their work on Raman spectroscopy. The work is important because it analyzes the surface of the hair shaft, and can show traces of explosives, illicit drugs, gunshot residue or bodily fluids.