The investigator must be knowledgeable in the areas of manufacture, materials, and detonation of explosive materials. Another important aspect is the knowledge of the mental states and psychological disorders that lead to random and intentional bombings. Crime Scene Reconstruction is the interpretation of the evidence to recreate the circumstances of the crime. Each crime scene is unique and must be evaluated individually. This is beneficial in cases where only small quantities of evidence are discovered.
Toxicologists examine body fluids and organs for the presence of poisons, alcohol, and drugs.
A toxicologist detects, identifies, and quantifies minute amounts of these substances for further evaluation. The basic principle of firearms examination is based on the fact that most machined parts will have unique marks, which can be transfered to other surfaces. Almost all gun barrels, as well as the machined areas in the weapon's firing mechanism, leave unique marks on bullets fired through the barrel and on cartridge cases worked through the firearm. A firearms examiner deals with the analysis of both firearms and ammunition of all types. The Firearms Examiner also determines whether a bullet originated from a suspect firearm.