• Forensic rules for storing evidence in plastic are outlined for investigators.crime examination (investigation) image by stassad from Fotolia.com
  
  The forensic rules of procedure for the collection of various types of evidence helps ensure a successful investigation and prosecution of a crime. Forensic guidelines outline appropriate rules for collecting, identifying and preserving evidence, including storing physical evidence in plastic. If investigators don't follow rules, they can contaminate evidence. When collecting tissue, organs, bones, weapons or any arson-related materials, investigators always must place these items in plastic.
  
  

Tissue, Organs and Bone Evidence

• When forensic anthropologists arrive at the scene of a crime, they are responsible for immediately collecting, preserving and recording physical evidence, which can include tissue, organs or bones. These specialists can identify a body and determine the cause of death. According to the Maryland State Police Forensic Sciences Division, when collecting evidence of fresh or dried tissue, organs or bones, place these items efficiently in an "airtight plastic container, and freeze them at O degrees Celsius, or below. Investigators must place every item in a separate plastic container and label each.
  
  

Weapons and Firearms Evidence

• Firearms, knives and many other weapons are used in committing various crimes; these can include such serious offenses as homicide, robbery or drug trafficking. According to the U.S. Fish & Wildlife Service, when investigators retrieve incriminating evidence such as a firearm from a crime scene, the firearm should always be unloaded. If there is more than one firearm, place each in a separate plastic hard case, properly labeled and locked. Once the firearm is efficiently packaged and identified, an agent should deliver it to the laboratory personally (if at all possible) or ship it to the laboratory. The key to the lock on the firearms' case, should be shipped separately. Investigators who retrieve a knife from a crime scene should store the knife in a sturdy plastic hard case with a lock. If there is more than one knife, each knife should be labeled and packaged in a separate locked plastic case.
  
  

Fire and Explosions Investigations

• According to the U.S. Department of Justice, crime scene investigators should ensure that all evidence is properly documented and that the integrity of the evidence is always maintained. During the course of an investigation of a fire and explosions crime scene, detectives collecting evidence of arson, such as "...large pieces of wood, upholstery and wallboard which are too large to fit in cans," must place all the evidence in separate plastic bags and seal each item with heat, according to Crime Scene Investigator Network. The laboratory must examine one plastic bag when it arrives with each order to ensure that it is acceptable. All evidence placed in the plastic bag should be labeled. According to the FBI, any evidence of ignitable liquid that is collected should be placed in heat-sealed plastic bags approved for fire debris; the bags should not be completely filled but should be packed carefully to prevent damage.