The field of crime scene processing is extremely demanding and ever changing. Demands from the scientific and legal communities influence the crime scene investigator's everyday activities. The scientific community focuses on the examination of evidence collected at a crime scene. Investigators and crime scene specialists are responsible for identifying, securing, documenting and preserving biological evidence recovered from a crime scene. Legal considerations include scrutiny of procedures used at crime scenes and chain of custody. The investigator must also know when and how to make decisions to obtain written consent or a search warrant to assure that the evidence will be admissible in court and not subject to a motion to suppress.
DNA databases provide law enforcement officers with the ability to identify potential suspects when no prior suspect existed. The development and expansion of databases that contain DNA profiles at the local, state and national levels have greatly enhanced law enforcement's ability to solve cases with DNA evidence. These databases are operated using the Combined DNA Index System (CODIS), a software program that permits the cross-comparison of DNA profiles developed from biological evidence found at crime scenes and also of known offender profiles.
This training describes handling the most common types of biological evidence that may be encountered. This general information is subject to agency protocols for handling evidence.