Effective February 1, 2022, requests for Fire Debris examinations will only be accepted by ADFS for cases involving crimes against persons (i.e. fatalities). For those cases, ADFS will continue to provide the necessary testing for your office, free of charge, under ADFS’ professional services contract with an accredited fee for service laboratory. Fire Debris cases involving crimes against property will no longer be accepted by ADFS after February 1, 2022.
General Evidence Collection Guidance:
Evidence Documentation
Arson must be regarded as a possible, if not probable, cause of every fire investigated. The value of physical evidence depends upon the proper documentation, collection, and preservation of the evidence from the time of its initial discovery and collection to its subsequent examination and analyses.
Movement or collection of the physical evidence should be avoided until the item has been photographed and documented as to location. Documentation can best be accomplished through notes at the scene, written reports, sketches, and diagrams with accurate measurements and photography. The diagramming and photography should always be completed before the physical evidence is moved or disturbed.
Evidence Collection
1. Ignitable liquid samples - When a liquid sample is found at the scene, a sample of the liquid should be submitted for analysis.
Ignitable liquids found at the scene (charcoal starters, etc.) should be collected for comparison standards.
The liquid should be collected in a small vial with screw-on caps made of phenolic resin, polyethylene, or Teflon. Sterile cotton balls or gauze pads may be used to adsorb the liquid sample if a vial is not available. The cotton balls or gauze pads are subsequently sealed in a new, unused metal paint can. An unused sample of cotton balls or gauze pads should be submitted to the laboratory for comparison.
Never submit more than a half of cup of liquid to the laboratory for analysis.
2. Ignitable liquids absorbed on porous materials - Ignitable liquids may be trapped in porous materials such as a concrete floor.
If the concrete floor can not be removed, an absorbent material such as lime or flour may be spread over the area, allowed to stand for 20-30 minutes and then collected for analyses.
Clean tools and containers for the recovery step must be used since the absorbent may be easily contaminated.
A sample of the unused absorbent should be preserved for analysis as a comparison sample.
3. Ignitable liquids absorbed by solid materials - Ignitable liquids may be absorbed by solid materials at the fire scene. A few examples of solid materials that may be collected at the fire scene are: wood, carpet, carpet padding, furniture, concrete, cloth material, clothing, shoes, etc.
4.
Soil - Soil samples should be submitted to the laboratory as soon as possible. Bacteria in soil can “eat” petroleum-based products.
It has been our experience that positive samples after six weeks of storage were negative for petroleum-based product.
Note:
Collection of physical evidence after the fire scene has been released requires a search warrant.
Evidence Containers
1.Metal cans: quart, one-gallon, five-gallon
2.Nylon fire debris bags
DO NOT use plastic bags since ignitable liquids will pass out through the plastic, and never use paper bags or envelopes.