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Fingerprint on a Ball Python. Credit: USFWS

Special Agents and Wildlife Inspectors

An evidence tag.
An evidence tag . Credit: USFWS


This page covers collection, preservation, and documentation prior to sending items to the lab.

Quick Links to:

Carcasses and Bushmeat
Tissue collection for DNA analysis
Non-Perishable Evidence
Latent Prints
Expended Bullets and Cartridge Cases
Live Ammunition
Pesticides and other Chemicals


Perishable evidence includes whole carcasses, animal parts and tissue samples which will decompose if not maintained under refrigerated or frozen conditions. Please call the Laboratory for special shipping instructions.

Note on Infectious Diseases

The National Fish and Wildlife Forensics Laboratory is not an infectious disease diagnostic Laboratory.

Evidence items which are known or suspected to be infected with pathogenic organisms and which represent a real or perceived zoonotic disease threat, including, but not limited to perishable mammalian carcasses or tissues, i.e., ‘Bushmeat’, etc., from foreign origins - or primate carcasses or tissues from domestic sources, CANNOT be sent to the Laboratory without special handling, packaging, labeling and shipping containment identified in public health regulations of 42 CFR Part 72 and 49 CFR Part 173.134.

You must call the Lab and discuss your submission prior to shipment. When clearance is granted, in addition to the requirements of 42 CFR Part 72 and 49 CFR Part 173.134, you must label your shipment with “EE” to alert Laboratory staff.

Call the Laboratory if significant numbers of animals or tissue samples are involved in your case.

Note on Pesticide-Laced Bait Evidence 

Bait evidence, including carcasses on which suspected pesticides have been placed, cannot be shipped to the Lab using these guidelines. Follow the Hazardous Materials Evidence packaging and shipping guidelines to collect and ship sub-samples from suspected bait evidence.

Note on Noxious Odors
Any perishable evidence item that clearly has a noxious odor (from decomposition, etc.) is considered a Class 9, Miscellaneous Hazardous Material under 49 CFR 173.140 (a).

To avoid having to package and ship according to Class 9 regulations, all items which exhibit a noxious odor must be contained in multiple sealed plastic bags to eliminate the odor.  SKUNKS - Do not send skunks to the Laboratory. No amount of wrapping will eliminate the odor.



Caviar collection requires the use of a special ‘kit’ provided by the Laboratory. Call the Laboratory if you are in need of a kit.

Each collection kit contains:

1 Large Screwcap Tube (50 mL volume)
1 Wooden Tongue Depressor
4 Latex Gloves (Powder Free)
1 Zip-Lock Plastic Bag

Collection:   For caviar shipments comprised of 100-1000 tins (i.e., 50 gram, 113 gram, 500 gram or 1.8 kilogram weights), randomly identify 30 tins for sampling.  If there are fewer than 30 tins in the shipment, sample every tin.  With a permanent marking pen, label each tin to be sampled as well as the box/carton from which each tin is selected with the Seizure Tag # for the case and the item # for the tin.  Maintain selected caviar tins at a cool temperature and out of direct sunlight.

  1. Open a collection kit and label the screwcap tube with the identifier corresponding to a labeled caviar tin.  Record the identifier on the bag you received with the collection kit.
  1. Put on latex gloves, open the labeled caviar tin and discard gloves.
  1. Put on clean latex gloves and use the tongue depressor to transfer about a teaspoon of caviar (100 eggs) from the labeled tin into the labeled screwcap tube.  Discard the tongue depressor and gloves.
  1. Close the tube securely and seal it in the labeled plastic bag.  Close the caviar tin and return it to its original labeled box/carton.
  1. Repeat steps 2-5 twenty-nine more times.

Preservation: Refrigerate...DO NOT FREEZE!



The National Fish and Wildlife Forensics Laboratory (NFWFL) Genetics Section capabilities include Determination of Species Origin, Gender Origin, Individual Identity, and Population Assignment for selected species.  Contact the Genetics Section to discuss specifics regarding the types of analysis that can be conducted on different species. 

When you have a carcass to sample, do not simply:  1) Dab blood/serum from the carcass with a paper towel; 2) Randomly pull or cut hairs; or 3) Take a slice of the hide consisting predominately of hair, fat or connective tissue.  These types of evidence are not optimal and can lead to inconclusive results.

Record specific location information for each sample submitted.  This is especially important for kill sites.  UTM or GPS coordinates work well.  Location information is valuable when referencing existing databases.


Tissue:  The fresher the better.  Muscle tissue is best.  Organs such as the heart and liver are good if fresh.  Collect about a dime sized piece and place in a sealable plastic bag. Do not store tissue samples in paper bags. The more degraded the tissue is the more you want to collect--up to a golf ball size piece. 

Blood:   There are a number of ways to lift, collect, and store blood stains.  Though there are unique crime scenes, such as blood in snow, in most cases the following technique for collection and storing of blood samples should suffice.  Contact the Genetics Section for alternative collection methods.

Dried blood can be lifted off a substrate using cotton gauze or swabs.  Wet the gauze or swab with water and lift the sample from as defined an area as possible.  Concentrate the material on as small a piece of gauze or on as few swabs as practical.  In other words, don't lift a dime sized piece of blood onto a paper towel.  Collect samples so as to minimize the chance of having the blood of more than one animal present on the swab or gauze.  Dried blood on substrates such as leaves, rocks, clothes, etc. should be collected and submitted on the substrate when practical.  Wet blood should be lifted onto swabs or gauze.


Tissue:   Freeze as soon as possible.  (Beaded desiccants can be used to dry small pieces of soft tissue and allow for storage at room temperature.  The NFWFL Genetics Section has a protocol available upon request regarding the use of beaded desiccants for sample collection and storage.) 

Blood:   IMPORTANT!!  The blood stains must be dried thoroughly.  Store and ship these samples at room temperature in paper NOT plastic.



Non-perishable evidence includes all types of evidence that do not need to be frozen or refrigerated, including, but not limited to, ivory, feathers, and sea-turtle shells.

Collection:  In general and where practical or otherwise directed below, all evidence should be individually labeled and bagged in a plastic, paper or cardboard container. 

Preservation:  Maintain at room temperature in dry conditions.



Collection and Preservation:

  1. Use cotton gloves to pick up the evidence items in areas not likely to have latent prints, being careful not to wipe or brush against surfaces which may bear latent prints.
  1. 2a. Fasten the evidence items to a rigid surface (or suspend the item inside a box) with wire, zip-ties, or string to prevent shifting and contact with other evidence items or packaging.  Latent prints are package sensitive!  If you have ANY questions please call the Lab and talk to the Latent Print Examiner.
  1. 2b. Place documents and other paper-evidence in sealed manila envelopes. Do not write on the envelope with evidence inside.
  1. 2c. Place any developed latent lifts in sealed manila or mailing envelopes. Do not write on the envelope with evidence inside.
  1. Keep all items separate from each other to minimize destruction or contamination of latent prints.
  1. Place all separately packaged items into another inner shipping container labeled with the words “Latent Print Evidence.”   

Note: Include all known and relevant information about the item (e.g.: flashlight was found in snow after being lost for one week … was air dried, secured into an evidence container … and shipped to the Lab).

Things to avoid while collecting, packaging and shipping evidence items suspected of bearing latent prints:

  • DO NOT cover items to be examined for latent prints with evidence tape.
  • DO NOT handle latent print evidence with thin disposable plastic or latex gloves.  Whenever possible use cotton gloves and handle as little as possible!
  • DO NOT package items suspected of having latent print evidence in cotton, cloth, styrofoam peanuts, or any other packaging that might smudge or wipe away latent prints.




If you have any concerns about the function/safety of a firearm, be sure to call the Firearms Examiner and state those concerns on your Evidence Submittal Form or in your transmittal letter.

Collection:  The firearm should be minimally handled to avoid loss or destruction of evidence. Do not allow objects to enter or contact the firearm's barrel, chamber or other operating surface.  Include all accessories (such as a scope or magazine, etc.) that may have been attached to the firearm at the time of the shooting incident.

We recommend that you purchase a sturdy, cushioned-lined, hard plastic or metal gun case for shipping. A locking case is preferred - ship the key separately. Securely tape all clasps to prevent opening.  

Preservation: Maintain at room temperature in dry conditions.



Collection:  Do not personally test fire a firearm and collect cartridge cases, shot shells, bullets for comparison purposes. Laboratory personnel will test fire all firearms.  

Preservation: Do not send wet or damp cartridge cases, shot shells, or expended bullets.  If these items are recovered wet or damp, allow them to dry before packaging. A water wash (no rubbing or scrubbing!) to remove excess organic material is encouraged unless genetic examinations are to be performed on the organic material.  In that case, allow the blood or tissue to air-dry and then package the items in paper wrap, not plastic, and ship following the general package/shipping guidelines. Be sure to indicate that the firearms evidence has blood/tissue materials that require additional examination.

Package dry cartridge cases shot shells and expended bullets in cotton. Do not use plastic bags or other containers which may permit the growth of bacteria which is potentially harmful to micro-striated detail on bullets or promote rusting on cartridge cases and shot shells.

Individually wrap or otherwise protect all cases, shells and discharged bullets to prevent rubbing and abrasion during transit.  

The outer shipping container must be strong enough to prevent compression damage to all items in transit.



We discourage sending live ammunition to the Laboratory. Refer to section for packaging Live Ammunition.

Collection and Preservation: If you are asked by Lab staff to ship live ammunition:

Bullets must be protected from scratches and damage.

Primers must be protected from accidental detonation.



Pesticides and other chemicals must be shipped following U.S. Department of Transportation Regulations.  Refer to section 3.1.3… for details on shipping these items.

Collection: The Laboratory has special collection and packaging kits for shipping hazardous materials evidence to the Laboratory.  These kits will allow you to prepare shipments of hazardous evidence in a manner which meets DOT regulations.  Call the Laboratory if you need a kit.   

Each kit contains:

(3) 15 ml plastic tubes with screw cap lids
(6) cotton-tipped applicators
(1) padded envelope
(1) 8 oz plastic container with screw cap lid
(2) zip-lock bags
(2) pair of latex gloves
(1) U.S. Department of Transportation label 

Be extremely careful when handling any chemical. Use rubber gloves to protect your hands and be careful of your clothing, shoes, tools, etc. which could transfer to your vehicle, office and home.   

Pure Samples – chemicals that come straight from a bottle or can.

  1. Coat the two cotton-tipped applicators with sample (solid or liquid).
  2. USDOT regulation 49 CFR 173.4 (a)(1)(iii) allows you to place up to 1 gram or 1 milliliter of sample into the tube. 
  3. Leave the applicators in the tube and tightly secure the screw cap.
  4. If possible, always collect three tubes from the same source.
  5. Labeled the three tubes as one item on the evidence submittal form.
  6. No more than 300 tubes containing pure sample can be shipped in the same shipping container.                      

Diluted Samples - include solid samples such as distinctly visible granules, powders or pastes or liquid samples with a distinctive color/odor on bait carcasses (sheep, chickens, etc.) or in the soil, corn, seeds or other substrates.

  1. USDOT allows you to fill the tube completely with dilute sample.
  2. Tightly secure the screw cap.
  3. If possible, always collect three tubes from the same source.
  4. Labeled the three tubes as one item on the evidence submittal form.
  5. No more than 300 tubes containing pure sample can be shipped in the same shipping container.                      

Preservation: Keep samples cool and dry.


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