Hairs are another form of trace evidence which are often found at crime scenes and forensic hair analysis is the study of such evidence. Physical contact between people may result in head, body or pubic hairs being transferred from one person to another. Hairs may be found adhering to broken glass or woodwork at the point of entry at a burglary scene.
Forensic hair analysis and the examination of hair roots can be important when investigating violent crime. The appearance of the root will differ depending on whether the hair fell out or whether it was pulled out by force. It may also be possible to determine if hair has been burned cut or crushed. Forensic hair examination can also provide information about racial origins. Hair which has been died may also prove characteristic of a particular suspect.
If the root and sheath material are still adhering to hairs then they can also be used for DNA profiling and compared to a DNA reference sample from a suspect.
Hairs which are suspected to originate from animal sources can also be examined and attributed to a particular species of animal (e.g. dog, cat, rabbit etc.) or if they are unusual or multi- coloured they may indicate a particular variety (e.g. Siamese cat).
The body of a murdered person is found dumped in woodland. A suspect (the owner of a large black and tan German Shepherd dog) who was known to the victim is apprehended. The clothing of the victim is sent to a forensic laboratory to recover any trace evidence from it and tan animal hairs are recovered from that clothing. The prosecution case is that the victim was carried to the woods in the back of the suspect’s estate car, the carpet of which was covered in hairs from his dog.
Review the forensic findings of the prosecution in respect of the hair evidence.
Re-examine the hairs recovered from the victims clothing to confirm or refute that they are dog hairs and whether or not they could be fox hairs, as the body was dumped in woodland.
Conduct a secondary forensic hair analysis to compare the hairs from the suspects dog to those recovered from the clothing of the deceased and if they prove to be similar, comment on the strength of that evidence (e.g. does that similarity mean similar coloured dog, same type of dog or the particular dog owned by the suspect).
Provide a detailed forensic expert witness report commenting on all issues raised by the defence counsel together with expert opinion on any other aspects found to be relevant to the defendants case during the investigation.