Crime scene investigation is a complex, as well as, intricate process. Since not all crime scenes are the same, the process of investigating them is not fixed. In fact, there is a multitude of individual tactics and procedures used by investigators to perform a successful crime scene investigation. There is, in fact, a checklist in the brain of every crime scene investigator. Though there is no uniform procedure of crime scene investigation, usually there are some universal steps followed by every investigator to conduct a successful crime scene investigation. From collecting shreds of evidence, photographing the crime location, to taking fingerprints, there are some crucial steps in every investigation.
1. Securing the crime scene
The crime scene investigator (CSI) on reaching the scene first establishes the boundaries of the crime scene. This is done by using a crime scene tape and putting sentry at all possible entrances. The area or structure must be secured by controlling ingress and egress so that no further disruption can be caused to any potential physical evidence.
Once the investigator locates the main area of the disturbance, a radius of the focal point with all the immediate physical evidence is to be created. Usually, investigators prefer to create a large radius so that any potential evidence is not missed or disturbed by spectators. Mostly, a yellow crime scene tape or rope or cones are used as a barrier and a common entryway is created. Each and every person entering and leaving the area is to be documented. In addition to this, CSI must identify and remove any hazardous materials or weapons from the location.
2. Take the first round survey
Evidence plays a central role in prosecuting a case. For collecting evidence, CSI conducts the first round of crime scene survey. He walks around the exterior of the structure to check for obvious evidence, such as open windows, damaged doors, or ladders. While conducting the scene walkthrough, the lead investigator will identify and take photos of important evidence. Then he searches for evidence inside the building. It is at this time that he/she will take photographs of the scene, note weather conditions, check if the lights were on or off, note down the exact position of items such as furniture, the presence of any smells, etc.
3. Assess the location and note down details
The first look of the crime scene gives an idea about what type of evidence must be present at the location. The CSI think what must have happened here when it happened and what evidence are to be looked for. This includes the possibility of removing blood and other evidence by the first responders or family members, signs of struggle, or visible footprints in the blood. On the basis of all the physical evidence available, the CSI prepares a narrative of the scene to give the impression of the scene.
4. Conduct a detailed search
Now, it’s time to locate even the smallest particle of evidence, as well as, collect fingerprints. This includes using a vacuum to collect any potential microparticle evidence such as hair and fibers. Also, all the potential physical evidences are captured photographically with a medium range and close-up shots. In addition to this, CSI also prepares a rough sketch of the scene. Sometimes, for more complicated cases, the investigator may use videographer to present a better idea of the scene to a jury. It is extremely important to keep all the evidences in proper containers. The evidences with blood stains must never be packed in plastic bags to prevent them from decomposition. Also, all the evidences must be properly labeled.
5. Perform a Final Survey
Proper crime scene investigation is fundamental in deciding the case in the future. Thus, a skilled investigator makes sure that no a single evidence goes ignored. In the final survey, each team member participates so that no potential evidence is left by chance and to ensure that there is no error in the documentation. Once the team is satisfied, the crime scene is released.