Don’t mishandle forensic evidence: Take these 4 steps

Here are ways to protect the forensic evidence you collect, recommended by Diane DeHart, PA, coordinator of the Sexual Assault Nurse Examiner (SANE) Program at Harborview Center for Sexual Assault and Traumatic Stress in Seattle, WA:

1. Don’t break the chain of custody.

"No matter how meticulously you collect the evidence, if there is a lapse of time during which it cannot be accounted for, there is a chance that it will not be admissible in court," DeHart warns. She recommends the following:

• Keep the evidence in your sight or in the sight of a person who agrees to protect it until it is placed in a secure, locked area or transferred to the receiving officer.

• If you must leave the evidence, ask another staff member to take possession of it, and then have that individual sign the kit or a chain-of-custody form.

• Sign, date, and time all packages containing evidence. Most kits will have a specific place to note these details.

• Place an evidence seal or patient label over the flap of the evidence envelope (or over the folded edge of a bag). Date and initial this seal so that your writing goes over the seal and onto the envelope or package. This shows not only that the evidence was collected by the person initialing it, but also that there has been no tampering with it.

• If you forget to place something in the kit, simply open it and include the item. Re-seal with new evidence tape, re-initial, and indicate in writing directly on the kit that this was done.

2. Label evidence properly.

Envelopes or boxes containing swabs and slides used to collect evidence must all be labeled with the patient’s name, date and time of collection, and name of the nurse collecting the evidence, says Valerie Sievers, MSN, RN, CNS, CEN, SANE-A, clinical forensic nurse specialist and SANE Coordinator at Colorado Coalition Against Sexual Assault in Denver. She says that the goal is to show that evidence was accounted for at all times.

3. Avoid contaminating evidence.

Your goal should be to maintain the evidence in its original state, or as close to it as possible, says Trudy A. Meehan, RN, CHE, director of emergency services at East Jefferson General Hospital in Metairie, LA. Cut clothing carefully, she advises. Ideally, clothing should be removed without being cut, so as not to destroy evidence such as knife and bullet damage, Meehan says. If you must cut garments, cut around damaged areas, she says. Also, Meehan stresses the importance of wearing gloves, so your fingerprints don’t end up next to or over evidence.

Change to a new pair of gloves for each site of collection, says DeHart. "This prevents transfer of DNA from one site to another, which may compromise the very reason for collection of evidence: corroboration of the victim’s account of what happened," she explains.

4. Seal containers appropriately.

When evidence was collected in one suspected drug-facilitated sexual assault case, the urine container was not properly sealed, labeled, and bagged, recalls Sievers. "During transport, urine leaked on the envelope containing the contents of the sexual assault kit, contaminating all the evidence," she says. Evidence containers must be appropriately sealed to avoid contamination or loss, says Sievers. "Clothing items should be packaged individually so as to eliminate the potential for cross-contamination of trace evidence and also should be dried as much as possible before packaging," she says.

To avoid cross-contamination, place all items in individually sealed evidence containers, she says. Envelopes that contain trace evidence or swabs must be sealed shut by moistening the adhesive with water, taping the flap shut with tape, and initialing the tape, says Sievers. Cardboard slide carriers should be securely taped shut so the slides don’t fall out into the bottom of the kit envelope, she adds.

All is not lost if you accidentally contaminate evidence, such as dropping a swab on the floor while carrying it to the drying area, DeHart emphasizes. A note on the evidence envelope will alert the criminologist to the possibility of foreign material and does not render evidence unusable, she says.