Everything is photographed before it is handled.
All objects are picked up while wearing gloves and using
tweezers. Each object is packaged separately in a box, metal can,
or paper bag/envelope. Nothing is ever packaged in plastic.
Plastic retains heat and moisture, both of which promote growth of
bacteria and mold. Bacteria and mold can contaminate or destroy
evidence. Guns must be emptied and tied in a manner that prevents
accidental firing. Known samples from surrounding areas are taken
whenever possible. With soil, that means 1 cup is collected from
several locations. Don't try to match tools to their marks while
on site. This may compromise the evidence. Send an evidence
submission form to each delivery site. Hand deliver chemicals,
live ammunition, explosives, and biohazardous materials.
Fingerprints may be classified as one of three types of impressions:
plastic: in a soft, pliable surface (mud)
visible: easily seen (blood or ink)
latent: not visible but still present, may be developed (use dust)
Tools and damaged areas need to have casts made after
photos are taken. Known standards are collected for
comparisons. Bite marks and open wounds are photographed and
washed in distilled water. Water is collected to check for saliva.