Fire Scene Evidence Collection Guide
Impressions
Known Footwear
Detailed Procedure:
Footwear is typically collected for identification and/or comparison with a questioned impression. If footwear is being collected from a suspect, be sure that any warrant and/or consent procedures have been followed.
To collect known footwear:
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Photograph the footwear in place.
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Wear new, unused, clean latex or nitrile gloves.
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If the footwear is wet, place it on new, clean, dry paper in a draft-free, dry location that is secure, ensuring no one will touch, step on, remove, or displace the footwear. Allow the footwear to air dry, unless it will be examined for ignitable liquids.
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When the footwear is dry, package it in an appropriately sized, air-permeable, but closed container, such as a cardboard box. Take care not to bend or alter the footwear, especially the treads. The footwear may contain trace evidence. Ensure that the container is tightly closed so small particles cannot escape through cracks.
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If the footwear is to be examined for ignitable liquid residue, then it should NOT be dried and should instead be packaged in an airtight container such as a new, unused metal paint can of sufficient size. Consult your laboratory for guidance.
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There may be situations where drying the wet footwear will compromise evidence. For example, if you would need DNA analysis (which requires breathable packaging) and ignitable liquid analysis (which requires air-tight packaging) done on a piece of evidence, the lab may tell you to package it in an air-tight container and bring it to the lab immediately so that the fire debris analysts can collect their evidence before the item is taken out of the air-tight container and dried for subsequent DNA analysis. Therefore, be sure to check with your laboratory.
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Label the container with identifying information, including case number, date, exhibit number, a brief description, and your name.
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Insert the item into the container.
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Seal the container with evidence tape. Initial and date the tape.
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Store the item in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.
Laboratory examination of known footwear:
Known footwear can be compared to questioned impressions left at a scene. Associations may be made by comparing tread design and tread design orientation. A positive match may be made if the questioned impression has sufficient individualizing or unique features (eg: cuts, nicks, wear pattern) in common with the known footwear. Evidence may be present in/on the tread (eg: soil, blood) that can be compared to known samples from the persons, places, and objects.
Source:
Crime Scene and Evidence Collection Handbook. Bureau of Alcohol, Tobacco, Firearms and Explosives. 2005.