At an arson scene,the collection of a substrate control would require the arson investigator to:

Question

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The purpose of collecting a substrate control is to have a comparison sample that can be used to eliminate the possibility of false positives. By collecting a sample of surface material near the fire's origin that was not exposed to the accelerant, the investigator can compare it to other samples collected from areas where the accelerant may have been used. This will help determine if any accelerants were actually present or if the results are a result of contamination. Collecting a sample from the center of a potential accelerant stain (choice A) or collecting a sample of the vapors at the fire origin (choice D) would not be appropriate for collecting a substrate control. Collecting samples of surface material from areas far away from the fire's origin (choice B) may not be relevant to the investigation and would not be useful in eliminating false positives.

At an Arson Scene,the Collection of a Substrate Control Would