Science & Research
Volume IV - 14.6 Sample Handling
Orientation and Training
|VERSION NO.: 1.5|
Section 14 - Complaints & Tampering
|EFFECTIVE DATE: |
It is important that judicious attention to detail occur in the handling of complaint/tampering samples in order to maintain sample integrity and avoid overlooking or damaging evidence. Carefully document chain of custody and storage conditions. Preserve as much suspect material as possible and preserve forensic evidence. Unless otherwise notified by submitting officials, protect fingerprint evidence by wearing cloth gloves over vinyl gloves or latex gloves and using tongs or forceps for handling the sample on edges, seams, and corners (i.e., away from potential fingerprint regions). As much of the packaging and product as possible should be left undisturbed. It is imperative to document every step of the examination and every observation in writing as well as by photodocumentation (film or digital photography or imaging).
(Important!) Obtain a gross sample weight, (liquid or solid) before proceeding with the analysis. The sample may be weighed in the original container and the container weight subtracted later, if needed. The weight/volume may be needed for comparison to control samples, to determine the amount of product remaining, or to substantiate the amount consumed, etc.
Only one suspect sample should be processed at a time. A clean, new piece of evidence paper (roll paper, butcher paper, etc.) with the sample identification on one corner should be placed at the examination site. If the sample examination did not cause visible particles or residues to fall onto the paper, the paper can be discarded before proceeding with the analysis of other samples. If particles or residues are observed, fold and retain the paper with the sample.
Intact suspect sample cartons, boxes, bags, plastic film covers, etc. should be opened in a region that is not suspected as being the site of entry. Avoid opening along manufacturer seams or seals. Record and document any observations and sample treatment used in the examination of suspect samples.
Perform a thorough non-destructive physical examination (see Section 14.7) before proceeding to chemical analysis (Section 14.8). There may be a point where it is best to stop the examination and refer the sample to another law enforcement agency/lab with more familiarity with forensic techniques for some analyses such as lifting of fingerprints, matching glues, identifying particles in situ, etc. Any suspicious findings should immediately be discussed with lab management to determine a best course of action.
When sampling any portion of the suspect sample for analysis, use as little sample as possible to conserve the sample for confirmatory analysis or further tests that may need to be run by other specially equipped laboratories such as the Forensic Chemistry Center. Assure that the condition of the sample has been well documented before sampling. Ordinarily, the sample should not be homogenized. For example, if the sample consists of a liquid in a bottle with some particulate on the bottom, remove a portion of the liquid and remove a portion of the particulate and analyze them separately.