Body Materials
Objects
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.
Impressions
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.