Evidence Submission Guidelines - Minnesota Department of Public ...

7.0 General Evidence Collection
UNCONTROLLED COPY WHEN PRINTED
MN BCA Forensic Science Service
Evidence Submission Guidelines
Authorized by: DAS
Issue Date: 03/14/2013
Page 9 of 48 Pages
Proper packaging, identification, and sealing of evidence is imperative to its preservation and
integrity. The likeliness of laboratory personnel obtaining the greatest evidential value from the
submitted evidence is increased when proper collection techniques are followed. Remember that you
may be a potential source of contamination; therefore, it is crucial to wear latex or nitrile gloves
when handling evidence. Keep in mind to change gloves between handling different items of
evidence.
Evidence should be packaged separately so that cross contamination cannot occur. If the
potential for cross contamination does not exist, like items may be packaged together (e.g. inked
elimination prints, latent print lifts from a specific collection area). Evidence should be
packaged in their entirety. This will protect from further contact with other objects and to
possibly prevent loss of trace evidence. Evidence should be submitted dry (e.g. bloody clothing,
plant material). Evidence should be protected to avoid breakage and/or leakage. Only submit
items that need analysis.
Use new packaging material when preparing evidence to be submitted to the Minnesota BCA
Forensic Science Service. This will avoid the possibility of the evidence encountering a
contaminant within the previously used material. Packaging material is available in a variety of
shapes and sizes. Choose a size that is appropriate for the evidence (e.g. coin envelopes for trace
items). Appropriate packaging includes but is not limited to: paper bags or envelopes, sturdy
cardboard boxes, plastic bags, metal cans, and glass vials.
Paper material is suitable for a variety of evidence given its porous property which allows residual
moisture to escape. Paper bags are appropriate to use when submitting clothing evidence. Manila
envelopes are the preferred material when submitting trace samples or swabs.
Fig. 7- 1 and 7-2: Paper bags and manila envelopes are available in a variety of sizes and types. Envelopes are
available padded for evidence requiring special care. It is beneficial to have an assortment of sizes and types
available to ensure proper evidence packaging.