Detailed Procedure:

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To collect locks and keys:

1. Photograph the item in place

2. Wear new, unused, clean latex or nitrile gloves.

3. Locks and keys should be collected in separate containers for examination.

4. If the object is a loose key, place it in an appropriate container (envelope, box, etc.). Take care to collect the item by touching the sides so as not to disturb any latent prints that may be on the key. If necessary, secure the key in the container with ties so it does not rub against the packaging material. NEVER FIT A QUESTIONED KEY INTO A LOCK. Continue with Step 6 below.

5. If the item is a lock, use a properly cleaned saw or other tool (not gas-powered) to cut through the door (or other object) bearing the lock. If the entire item can be taken (eg: if it is a footlocker or strong box), take the entire item instead of cutting out the lock. When collecting, take care to touch the lock as little as possible so you do not disturb any latent prints that may be on the lock. If the lock bears a toolmark, protect the toolmark with clean paper. Continue with Step 6 below.

6. Seal the container with evidence tape, and initial and date the tape.

7. Label the container with identifying information, including case number, date, exhibit number, a brief description, and your name.

8. Store the item in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.

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Laboratory testing of locks and keys:

Examination of locks and keys may show attempts to open locks without keys, decoding of locks and keys, and association of locks and keys. In addition, other evidence such as toolmarks or fingerprints may be recovered for analysis. Locks and keys can bear skin cells (for touch DNA analysis) or other residue (for trace evidence analysis).

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Source:

Crime Scene and Evidence Collection Handbook. Bureau of Alcohol, Tobacco, Firearms and Explosives, 2005.