EVIDENCE RECOVERY PROTOCOL
When selecting detection, collection, and preservation methods and the processing sequence, consider the circumstances of the case, ambient conditions, the discriminatory power of the different techniques, and the need to preserve or collect other types of evidence. . Record the techniques used for detection, collection, and preservation of the evidentiary items and the location from which they are removed.
Methods used for detecting trace evidence include but are not limited to general visual searches; visual searches assisted by different types of illumination, such as oblique lighting and alternate light sources (UV, laser, high intensity); and visual searches assisted by magnification.
. Trace evidence recovery or collection techniques used should be the most direct and least intrusive technique or techniques practical. Collection techniques include picking, lifting, scraping, vacuum sweeping, combing, and clipping..1. Picking. Trace evidence may be separated from an item by using clean forceps or other implements. The collected samples should be immediately protected against loss or contamination.
Lifting. An adhesive-bearing substrate such as tape is repeatedly and firmly patted or rolled over the item causing loosely adhering trace evidence to stick to the tape. Do not overload the tape. The collected lifts are typically placed on a transparent backing (e.g., clear plastic sheeting, glass slides, and clear plastic or glass petri dishes). This protects against contamination and permits samples to be easily viewed and removed for further comparison.
. Scraping. A clean spatula or similar tool is used to dislodge trace evidence from an item onto a collection surface such as clean paper. The collected debris is immediately packaged in a manner to avoid sample loss. This technique is most often conducted within the laboratory in a controlled environment that reduces the risk of contamination or loss of the trace evidence.
. Vacuum Sweeping. A vacuum cleaner equipped with a filter trap is used to recover trace evidence from an item or area. The filter and its contents should be immediately packaged to avoid sample loss. The appropriate vacuum parts, filter, and trap must be changed and rigorously cleaned between each vacuuming to avoid contamination. Consider using this method subsequent to other collection techniques as it is indiscriminate and may result in the collection of a large amount of extraneous material.
. Combing. A clean comb or brush is used to recover trace evidence from the hair of an individual. The combing device and collected debris from the hair should be packaged together.
Clipping. Trace evidence can be recovered from fingernails by nail clipping, scraping, or both. Fingernails may be clipped with clean scissors or clippers and packaged in clean paper. Fingernails may be scraped with a clean implement to collect debris from under the fingernails. Package the collected debris and the scraping device as one unit, typically in clean paper. Commonly, fingernails from the right and left hands are packaged separately. This does not preclude the collection of each or any nail separately from all others, such as a nail with obvious damage.
. Appropriate preservation and packaging of trace evidence and items to be examined for trace evidence will vary. Appropriate packaging must prevent loss or contamination of the trace evidence.
All evidence packages must be properly sealed in a manner to prevent tampering and eliminate loss or contamination of the trace evidence through open edges.
Small or loose trace evidence must be secured in clean, unused primary containers such as paper packets or petri dishes. The primary container should then be appropriately secured in an envelope or paper bag.
. Large items, such as whole garments, should preferably be sealed individually in clean, unused packaging.
. Clothing and other items that are wet must be air dried as soon as possible, without exposure to heat or sunlight, in a secured area in a manner that will prevent loss or contamination of trace evidence. An arrangement to collect any trace evidence that may fall from the item during drying should be used.
. Small or manageable items at a crime scene that bear visible, firmly attached trace evidence should be documented, packaged intact, and transported to the laboratory for examination.
. Items at a crime scene that bear visible but easily lost trace evidence or items that are impractical to transport should be documented and the trace evidence collected by an appropriate technique.
. Personnel responsible for the detection and collection of trace evidence should be aware of the applicable laws governing search warrants, searches, and seizures within their jurisdiction.
Personnel should be aware that various types of evidence will be present during the processing of a crime scene or the examination of items submitted to the laboratory. Some types of evidence other than trace evidence may be more significant to a particular case and therefore should be given higher priority.