Forensic evidence

Information

Forensic evidence is material or traces of material that have been analysed by a forensic science laboratory.

Forensic evidence is collected by members of the Gardai who are specially trained for that purpose. The aim is to ensure that the samples are not compromised or contaminated in any way either during or after the collection of the sample.

Forensic science laboratories routinely closely examine materials such as paint, glass, soil, hair, fibres, firearm residues, fire accelerants and footprint samples. These samples may have been taken from the scene of the crime or may have been found on the victim or the suspect.

Forensic evidence has many uses:

• The presence of a material in itself may be significant, e.g., presence of firearms residue on a suspect's clothes,
• Samples of materials may be matched, e.g., fibres found on the suspect's jumper match the victim's blouse
• Unique marks may be identified e.g., footprints.

Forensic evidence may tend to prove that a suspect was at the scene of the crime. For example, where a window was broken by a burglar to get into a house, the suspect's clothing will be examined by the laboratory for small glass fragments. The window will also be examined for fibres that may have come from the burglar's clothing. See also DNA evidence.

When forensic evidence is introduced in court, it will usually be explained by an expert - a forensic scientist. The scientist will explain what was done with the sample in question and how it was analysed. The scientist will then explain the laboratory's findings.