Forensic evidence refers to items collected or information gathered using scientific methods for use in legal proceedings. There are many types of forensic evidence that can be obtained to help investigators solve crimes.
When investigators arrive at a crime scene, the first thing they do is secure the area to preserve any physical evidence. They want to ensure that the evidence collected is not contaminated in any way. Depending on the type of crime and the location of the crime scene, the technicians may be required to gather samples of several items for analysis.
Blood evidence is one example of forensic evidence that can be gathered at a crime scene. Technicians will take samples wherever it is found. They may also remove smaller objects from the scene for analysis at a crime lab.
The evidence will be examined to determine blood type. If the sample is large enough, there may be enough material to extract DNA evidence from it. Investigators expect to find a victim's blood at a crime scene, but they may also find the perpetrator's blood.
A detailed analysis of the evidence can help lead police to the person or persons who committed the crime. Along with blood evidence, investigators will be looking for samples of other bodily fluids, such as saliva or semen, that they can analyze for DNA evidence. While this forensic evidence may not be enough on its own to convict an accused person, it can serve to place that individual at the crime scene.
Investigators also gather samples of hairs when they are collecting evidence. Any fibers found at the scene are carefully picked up and placed in marked evidence collection containers for analysis. Any other materials found on or near a body are gathered as part of the investigative process.
A victim's body itself can also be a source of valuable evidence. A post-mortem examination can help investigators by revealing a time and cause of death for the individual. Part of this process involves removing hairs and fibers from the body, as well as taking fingernail scrapings for analysis.
Forensic accounting is another form of evidence gathering. This type of forensic evidence involves examining records and putting together a paper trail that can be used to prove fraud or other crimes. It is one of the tools that criminal investigators have at their disposal to bring lawbreakers to justice.