| Collection of standards | Evidence Officer procedure | Disposal |
Hair evidence is generally associated with crimes involving physical contact such as homicides, assaults, robberies, and hit and runs. A transfer of hair can occur between two individuals or an individual and a place or object. Such a transfer is valuable evidence in cases where the perpetrator is a stranger to the victim or an environment.
The root of a hair may contain enough DNA to perform DNA analysis on it. The amount of DNA in a hair root is very small and therefore contamination may occur if precautions are not taken. Do not touch hair evidence with your bare hands or with contaminated gloves (see figure 9).
Absent DNA analysis, a hair analyst will examine and compare evidence hair to a standard, basing his/her conclusion(s) on the microscopic features of the hair samples. Common conclusions include statements regarding the similarity or dissimilarity of the evidence hair to the standard, however, hair comparisons cannot determine identity to the degree that fingerprint or DNA analysis can.
IMPOUNDING OFFICER PROCEDURES
The following may be determined with hair examinations:
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The degree of similarity between evidence hairs and a hair standards |
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Determination of human or non-human |
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Determination of animal species |
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Determination of human body origin (e.g. head hair, pubic hair, etc.) |
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Determination of classic racial characteristics |
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Whether or not a human hair was forcibly removed or not |
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Alterations exhibited in a human head hair (e.g. bleached, dyed, etc.) |
Whole human head hairs and pubic hairs (where the root is present) generally have enough microscopic features to allow for a meaningful comparison to a standard. Hairs from other parts of the body, or hair fragments (where the root isn’t present), are typically not well suited for a comparison.
Hair evidence can be collected in a number of ways. The table below lists the various methods and when they are appropriate.
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Method |
Description |
Packaging |
When to Use |
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“Pick” method |
Using your gloved fingers or tweezers, carefully retrieve the hair taking care not to pinch, crush, or stretch it. |
Place hair into a paperfold, in a folded Post-It note, or paper envelope. |
For hairs you can see. |
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Vacuum sweepings |
Use a trace evidence vacuum cleaner equipped with special traps holding a piece of filter paper. Lightly vacuum the surface of interest. The goal is to collect trace evidence that is on the surface of the object, not to clean the object. |
Carefully remove filter trap, cover with the lid or cap, and package entire unit in a paper or plastic bag. |
For hairs you cannot see, or to be sure you have not missed any. Good on car seats, sections of carpeting, and other large surfaces. |
|
Adhesive lifts Not recommended |
Use fingerprint tape, cellophane tape, or other clear adhesive substrate and pat over the item. Take care not to miss any areas or allow the tape to become “overloaded.” Post-It notes may also be used for small areas. |
Stick adhesive tapes onto a clear, colorless plastic sheet (e.g. transparency film). Place into a paper envelope or bag. |
For hairs you cannot see, or to be sure you have not missed any. Good on car seats, surfaces of clothing, and other medium to large surfaces. |
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Scraping |
Use a clean spatula or long, flat tool to scrape the surfaces of an object onto a large, clean piece of paper. For this to work well, the object should be hanging or held up vertically over the paper, scraping downwards. |
Carefully shake any trace evidence on the paper to the center and fold the paper. Seal the paperfold and place into a paper envelope or bag. |
For hairs you cannot see. Works well on clothing or other pliable objects. |
Collect hair standards in the following manner:
Obtain standards from all possible sources (e.g. suspect, victim, and other individuals common to an environment).
Obtain standards as soon as possible after the crime occurred. Hair naturally changes in its characteristics over time because it is constantly growing. The standards should reflect the individual’s hair as close to the date of the crime as possible.
Obtain a minimum of 24 pulled and shed hairs from various areas around each body region (e.g. top of head, side of head, back of head, etc.) Collect loose hairs by combing the hair and collecting them onto clean paper.
Gather all the hairs collected from a single body region and place into a paperfold or paper envelope.
Seal and label the envelope with the individual’s name and the body region it was collected from.
Do not package paperfolds containing different individual’s hair in the same envelope, or package hair standards with hair evidence. This could allow cross contamination to occur.
STORAGE
Ensure proper packaging; refer to the example board in the evidence processing areas.
Place one barcode on the item and the corresponding barcode on the property receipt.
Place the item in a location best suited to the size of the item, and area specified by the evidence room guide.
Using the barcode reader, scan the location of the shelf and then scan the barcode that is affixed to the item.
Place the item in numerical order by case number.
Place submitted hair in freezer while awaiting transport to the state crime lab.
Upon return of the hair from the crime lab, following packaging procedures on the container.
Upon authorization or disposition of the case, see “General Disposition of Items.'
Revised 11/05/03