Evidence Collection

Scent Collection And Preservation

Scent is evidence, and should be properly collected and preserved, like all other evidence at a crime scene.

A properly preserved, uncontaminated scent article can be utilized over a period of time. The best way to protect the item is to seal it immediately after use and preserve the item in a freezer if possible. Experiments have been conducted using items kept for months, with success.

In criminal investigations, it is important to note exactly what is used as a scent article, where it was obtained, who handled the article, how it was packaged, and where the item was stored prior to court exhibit. Follow approved chain of custody procedures

Scent Material Collection On Scene

Scent is evidence every bit as much as a gun, knife, foot print or any other physical evidence, the only difference is that it cannot be seen.

To properly collect scent evidence:

Wear rubber gloves to help prevent further contamination.
Evidence should be collected and stored in a zip lock freezer bag and labeled as local requirements dictate for evidence identification. (To collect turn the bag inside out over your hand and use the inside of the bag as glove to prevent contamination. Pick up the article and pull the bag over it then zip lock it shut.)
If the item is too large, such as a car seat or a door knob, lay a sterile gauze pad on it and allow it to stay for 20-30 minutes, then collect the gauze pad as described above.

Don’t forget that the physical evidence we mentioned, the gun, knife or other item is also scent material and should not be handled by anyone except crime scene personnel. It can be used to scent a dog.

Remember, a missing person scene should be treated the same as a crime scene until the person is found. Keep all but essential personnel out of the immediate area.

Scent Material From Off Scene

If scent material is not available at the scene and is to be selected and transported by another person(s), the following techniques will help prevent contamination of the article.

DO NOT TOUCH. No one should come in physical contact with the item. It should be collected wearing clean rubber gloves and the item should be picked up by using a coat hanger, etc.

PLACE THE ITEM in a clean clear plastic (zip-lock) or paper bag, properly sealed, labeled and stored for future use. Do not use green, black or white garbage bags to collect or store scent articles, they are chemically treated to kill/control odors. (Note: Paper bags may allow scent material to be contaminated.

WHEN USING A FOOT PRINT, protect it from being walked on and attempt to keep people out of the immediate area.

WHEN USING A CAR SEAT, keep everyone out of the car. Normally, the dog will react to the last scent on the seat covering. If an Officer has entered the car, the Officer must remain on the scene until the dog team has arrived and his scent has been eliminated by the dog.

A properly preserved, uncontaminated scent article can be utilized over a period of time. The best way to protect the item is to seal it immediately after use and preserve the item in a freezer if possible. Experiments have been conducted using items kept for months, with success. In criminal investigations, it is important to note exactly what is used as a scent article, where it was obtained, who handled the article, how it was packaged, and where the item was stored prior to court exhibit

Proper scent collection and preservation can save lives, it can also assist in solving crimes.

Scent is the unique smell each person has. It is like a fingerprint, no two people are the same. A search dog has the olfactory sensitivity to distinguish between people. This ability is what allows us to follow a person through a crowded arena or across a parking lot.

As the first officer on a crime scene or that of a missing person, you have the opportunity, really the obligation, to preserve all evidence at the scene. This includes scent evidence.