Evidence Collection Handbook - HAIR Evidence

Hair is a common type of evidence found in a variety of different types of criminal cases. The identification and examination of hair evidence can be performed by either a serologist or a trace analyst.

Value.

Hair evidence can be of particular value in the investigation and prosecution of a variety of criminal cases. These commonly include crimes such as : accident investigations, murders, rapes, assaults, and game law violations. Hair identifications and examinations provide important information to an investigation. In some cases, hair comparisons can provide important class characteristics similar to known standards. Microscopic comparisons cannot usually limit the source to a single individual, but with DNA analysis, further testing and additional results are now available.

Information determined.

1. With hair, the first step is to determine whether the sample is of human or animal origin.

2. If the hair is of animal origin, microscopic examinations of the internal features and of casts made of the hair scales often allow the analyst to identify the species from which it came.

3. If the hair is human, the possible race of the person, as well as the area of the body from which it originated, can usually be determined.

4. Hair treatment can also be determined. Indications of hair being bleached, dyed, crushed, cut, burned, or artificially waved often remain on individual hairs. Examination of the root may show whether the hair has been pulled out or has fallen out naturally.

5. Hair comparisons can also be made. Such comparisons can yield the following results:

   1. that the hairs are dissimilar, 

   2. that the hairs match in microscopic characteristics and originated either from the same person or from another whose hairs exhibit the same microscopic characteristics, or 

   3. that no conclusion could be reached.

6. If a microscopic comparison has been done, in some cases additional DNA analysis can be performed when necessary.

Evidence Collection.

1. Since hair evidence is generally small in nature, care should be taken to protect evidence from loss or contamination.

2. Several methods could be used in the detecting of hair evidence: visual searches, alternate light sources and searches with additional magnification.

3. Recovery of evidence should be the most direct but least intrusive technique practical. For hair evidence this could include: picking, scraping, combing, or vacuuming.

4. If the location of a foreign hair is important, they should be collected and packaged separately.

5. Wrap clothing or evidence items separately if collection is to be done by laboratory personnel.

6. If a hair comparison is requested, it is absolutely necessary that an adequate known sample be submitted. This consists of approximately thirty (30) pulled hair from the area of the body that the questioned hair is thought to have originated from. (If the foreign hair is head hair, the known sample needs to be head hair; if the foreign hair is pubic hair, the known sample needs to be pubic hair, etc.).

7. Known blood samples may also be necessary if DNA analysis is performed on a hair sample.

8. All items should be sealed and labeled for identification.
    

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