Hair analysis may refer to the chemical analysis of a hair sample, but can also refer to microscopic analysis or comparison. ... Analysts examine a number of different characteristics of hairs under a microscope, usually comparing hair taken from a crime scene and hair taken from a suspect.  Microscopic examination is also useful to distinguish between hair that is shed naturally and that which has been forcibly removed,  

Forensic scientists perform 3 major types of hair analysis: 
1.    testing the hair shaft for drugs or nutritional deficiencies in a person's system, 
2.    analyzing DNA collected from the root of the hair, and 
3.    viewing hair under a microscope to determine if it's from a particular person or animal.

A multi-phase examination process starts with the analyst establishing whether the unknown hair is of animal or human origin.

If it is an animal hair, the examiner can further identify it as belonging to a particular species, although it cannot be linked to a particular animal at the exclusion of other animals within the same species. Animal hairs found on items of evidence can link a suspect to a crime scene or a vehicle or location where a victim was held. Hairs from a pet the suspect owns, for example, may also be transferred to the victim when a suspect makes physical contact.

If the hair is human in origin, analysis can help to distinguish between individuals based on the arrangement, appearance and distribution of certain characteristics within different regions of the hair.