Evidence Collection and PPE - Study Notes

Investigators must retrieve and process evidence in a way that minimizes loss, degradation, or cross-contamination.
The goal of collection procedures is to maintain the integrity of evidence from the crime scene to the lab.

Blood (pooled, not dried)
- Collection: Absorb blood with sterile gauze or cloth.
- Preservation/Storage: Air dry at room temperature and refrigerate or freeze as soon as possible.
- Critical timing: May become unusable if not preserved by $48\ \text{hours}$ .
Blood (dried stain)
- Collection: Wrap clothing or object in clean paper and tape closed.
- If the item cannot be brought to the lab: the technician will scrape the dried stain with a clean knife or instrument into a clean envelope and seal it in an evidence container.
- Processing: Bring to lab for processing.
Saliva
- Collection: Collect on a sterile swab, gauze, or cotton cloth and allow to air dry.
- Storage: Place swab, cloth, or gauze in a clean paper bag and seal.
Hair
- Collection: Collect with tweezers or fingers and place in a paper bindle (clean paper folded to contain trace evidence).
- Packaging: Package in a clean envelope or paper evidence container.
Fibers
- Packaging: Package in a clean envelope or paper evidence container.
Glass
- Small pieces: Package directly into a paper bindle.
- Larger pieces: Place in a box with cotton or tissue to prevent edges from chipping or breaking off.
- Once in bindles, small glass pieces can be packed in boxes or canisters and labeled.
- Large pieces: Remain in the original box packed in, sealed, and labeled.

Paint
- Collect paint chips found at the scene in separate paper bindles.
- If paint is found on clothing, roll the clothing in clean paper and seal.
- Package in container, seal, and label.
Firearms
- Turn safety on and remove the magazine (if indicated).
- Do not take shotguns or rifles apart.
- Never submit a loaded weapon.
- Package in heavy cardboard or wooden box.
Tool Marks
- Wrap item with tool marks (or a portion of the item, e.g., a door jamb) in paper, seal, and label.
- If the item is too large or impractical to send to the lab, casts can be made of the tool marks.
- Casts are not always reliable and may not be very useful.
- Package in box or envelope as size indicates.
Drugs
- Put each drug evidence item in separate paper or specialty containers (e.g., PCP may require special containers).
- May package in a box or larger envelope.
- Prescription drugs should be left in the original container, sealed in an evidence container, and labeled.

Documents
- Put into cellophane or plastic envelopes.
- Do not mark or deface the documents in any way.
- Charred documents should be placed on top of cotton and placed in a box.
- Seal and label package and hand deliver to lab when possible.
- If mailed, use certified or registered mail.
Fingerprints
- Fingerprints can be lifted and then sealed and placed in an envelope.
- Photographed fingerprints should be labeled and scaled in the photo.
- Larger items should be handled as little as possible; even gloves or clean cloths used to lift the item can smear existing prints.
- The item should be packed in boxes and secured with string or peg board.
- Documents with possible fingerprints should be placed in cellophane or manila envelopes, sealed and labeled.
- Seal and label packages as indicated by size/type.
Bullets and Cartridge Cases
- Wrap bullets in paper and seal.
- Package in small boxes or envelopes.

Source: Georgia Virtual Learning (OER). You can download a copy of this Common Types of Evidence and Collection Procedures table here.

Videos illustrate tools used to process and collect evidence from:
- Bullet holes, prints and impressions, trace evidence, and blood.
Tools listed:
- Rods and lasers — Trajectory of bullets
- Dental stone and frames — Impressions such as shoe prints
- Electrostatic dust print lifter — Prints on tile or hard surfaces
- Vacuum with filter — Trace evidence
- Metal detector — Bullet casings or jewelry

During evidence collection, investigators wear PPE to protect both the evidence from contamination and themselves.
PPE may include: gloves, booties, hair covering, overalls, and a mask.
Why Wear PPE?
- To protect against exposure to bloodborne pathogens: $\text{hepatitis B}$ , $\text{hepatitis C}$ , and $\text{HIV}$ .
OSHA
- The Occupational Safety and Health Administration (OSHA) lists law enforcement personnel and forensic laboratory staff among those at risk for exposure to bloodborne pathogens.
- OSHA sets standards for both employers and employees to prevent on-the-job exposure to infectious materials.
Universal Precautions (a fundamental part of the bloodborne pathogen standard)
- Barrier protection — Gloves, coveralls, and shoe covers are worn if contact with infectious materials may occur.
- Glove change — Change gloves often to prevent contaminating surfaces (e.g., your writing pen).
- Eye and face protection — Protect against splashes or spatters with goggles.
- Wash hands — Wash hands after removing goggles and after removing other PPE such as booties or coveralls.
- No eating, drinking, or applying makeup — Avoid putting things in or near your mouth when potentially infectious materials are present.
- Clean equipment — Decontaminate after use with bleach, alcohol, or other appropriate disinfectant.

Pinch Glove (Step 1)
- Pinch the palm side of one glove near your wrist.
Slip Two Fingers Under Glove (Step 2)
- Hold the glove in the palm of your gloved hand.
- Slip two fingers under the glove at the wrist of the remaining gloved hand.
Pull Glove Off (Step 3)
- Pull the glove until it comes off, inside out.
- The first glove should end up inside the glove you just removed.
Dispose of Gloves and Wash Hands (Step 4)
- Dispose of gloves and other PPE in a proper biohazard container.
- Wash hands thoroughly with soap and running water, if available.
- If soap and water are not available or hands are not visibly soiled, use an alcohol-based hand sanitizer.

Final hygiene step: After removing PPE, wash hands with soap and running water if possible; otherwise, use an alcohol-based sanitizer when hands are not visibly soiled.