A crime-scene investigation aims to recognize, document and collect evidence at a crime scene. This evidence may include but is not limited to guns, clothes, personal items, footprints, tyre tracks, and fingerprints. Investigators will also talk to witnesses and gather every information that seems pertinent to the case. Once all the evidence is gathered, it is carefully examined and analysed in the forensic science laboratory and used to build a case against the suspect.
Also Read: Forensic Science in Criminal Investigation
Solving the crime will then depend on putting together the evidence to form a picture of what happened at the crime scene. Crime scene investigation is important in identifying suspects and arresting the offender. By following the right investigation procedures, law enforcement officials can build a strong case against the offender and assist in a speedy trial. The process can be complicated and time-consuming, but it is necessary to ensure that the offender is held accountable for their actions.
Also Read: Crime Scene: A Quick Review
How is it possible to identify the person who committed a crime?
A small amount of blood, hair, fibre, or a part of the skin or different materials can help a crime to be reconstructed and lead investigators to the responsible person.
For example, if a single strand of hair is found at the crime scene, it may be analyzed for DNA, which can then be compared to a suspect’s DNA to determine if they were present at the scene. Similarly, fingerprints left on objects at the crime scene can be compared to a database of known prints to identify a suspect.
(Note: Human hairs can be used to analyse nuclear DNA. The trace section helps the DNA section by looking at hairs to see if they can be used for DNA tests. The root ends of the hairs are looked at with a microscope to see if they are suitable for DNA Analysis.)
The following are the primary goals of the investigative process in a criminal or civil case. Crime scene investigators work to establish the fact that a crime has taken place and who committed the crime.
- Establish that a crime was actually committed;
- Identify and apprehend the suspect;
- Recover stolen property;
- Assist in the prosecution of the person.
WHO IS AN INVESTIGATOR?
An investigator is a person who conducts investigations to collect information and evidence related to crime. Investigators can work at various places, including law enforcement agencies, private investigation firms, and corporate security departments. They are responsible for collecting evidence, conducting interviews, and compiling reports. Investigators may have specialized training in areas such as forensic analysis, surveillance, computer crime and more, according to the demand of the job. They may also work closely with other professionals, such as forensic scientists, lawyers, and law enforcement officials. The ultimate goal of an investigator is to help uncover the truth and provide evidence that can be used to hold individuals accountable for their actions.
Who are Crime Scene Investigators?
Crime scene investigators are specially trained professionals responsible for collecting and preserving evidence found at a crime scene that may be useful in identifying and prosecuting the perpetrator of the crime. They work in law enforcement agencies and are part of the forensic science unit. They use specialized tools and techniques to collect and preserve evidence in a manner that will hold up in court. CSIs work closely with other law enforcement officials, such as detectives, to piece together the events that led up to the crime.
PURPOSE OF INVESTIGATION
The purpose of crime scene investigation (CSI) is to gather and analyze physical or biological evidence found at the scene of a crime to determine what happened, How it happened, who was involved, and ultimately, to help identify and prosecute the perpetrator(s) of the crime. In conclusion, criminal investigation and forensic science aim to discover the truth behind the scenes.
Process of Crime Scene Investigation
Crime scene investigation (CSI) is a multi-step process. The following are the steps that are followed in a typical crime scene investigation:
Secure and isolate the crime scene: The first and most important step in any crime scene investigation is to secure the scene. This involves setting up a perimeter around the crime scene and preventing unauthorized people from entering the area without permission.
Document the scene: The next step is to document the crime scene, which involves photographing, making videos, and sketching the area with evidence. It also involves recording every observation about the scene, such as the location of evidence, the position of the body (if there is one), and the general layout of the area.
Collect physical evidence: Following the documentation of the crime scene, the subsequent phase involves the search and collection of evidence. This can include fingerprints, DNA samples, hair and fibre samples, blood and other bodily fluids, and any weapons or other objects relevant to the investigation.
Analyze the evidence: after the collection of evidence they will send it to the lab for examination and analysis.
Testify in court: Sometimes, investigators may also be called to testify in court about the evidence they collected and analyzed.
Rules for Securing Crime Scenes
- A general rule of protecting the crime scene cannot be applied in every case.
- Who arrives first at the crime scene referred to as the first officer or first responder. The first officer’s top priority is to assist any injured person.
- To safeguard evidence and minimize contamination, access to the scene must be limited, and any persons found at the scene must be identified, documented, and removed.
- As additional officers arrive, they will begin procedures to isolate the area, using barricades and police tape to unauthorized persons from the scene.
Documenting The Crime Scene And The Evidence
Documenting the crime scene and the evidence typically involves four major tasks:
Note-taking: Investigators will take detailed notes about the crime scene, including its location, the condition of the area, the position of the evidence, and any other important information related to the case. The investigator will also keep a log of the persons entering and exiting the crime scene.
Photography: Investigators will take photographs of the crime scene and the evidence, both in overalls and close-up. This will include overall shots of the area and detailed shots of specific pieces of evidence.
Sketching: Investigators will create a rough and final sketch of the crime scene, including the position of the evidence, the layout of the area, and any other important details.
Videography: Investigators also use video to document the overall crime scene and the evidence.
Responsibilities Of Lead Investigators
A crime scene investigator’s (CSI) responsibilities can vary depending on the specific role and jurisdiction. Some general responsibilities of CSI may include:
Responding to crime scenes: CSIs are responsible for responding to crime scenes and conducting a thorough investigation.
Securing the crime scene: CSIs must secure the crime scene and ensure that no evidence is contaminated or destroyed. They set up a perimeter or other methods to control access to the scene.
Documenting the scene: The crime scene investigators document the crime scene and the evidence using note-taking, photography, sketching, and videography. They must ensure that all evidence is properly collected and packed.
Collecting and analyzing evidence: CSIs must collect, preserve and pack evidence found at the crime scene. They may use specialized tools and techniques to collect and preserve evidence while maintaining a chain of custody.
Testifying in court: CSIs may be required to testify in court regarding the evidence they collected and analyzed. They may be asked to explain their methods and findings to a judge or jury.
Collaborating with other professionals: CSIs collaborate with other professionals such as forensic scientists, detectives, and prosecutors. They must communicate effectively with others and work as part of a team.
Search Method for Crime Scene and Evidence
Several search methods can be used in crime scene investigation. Some of the most common ones used by Investigators include:
Grid search method: This involves dividing the crime scene into a grid and searching each section systematically.
Spiral search method: This involves starting at the centre of the crime scene and working outward in a spiral pattern.
Strip or line search method: This involves searching a crime scene straight from one end to the other.
Zone search method: This involves dividing the crime scene into specific zones and searching each one individually.
Wheel or ray search method: This involves searching from a central point outward in straight lines, like spokes on a wheel.
Link search method: This involves searching for evidence that may be connected to the crime, such as footprints or tire tracks.
The search method will depend on the specific circumstances and area of the crime scene and the type of evidence being searched for.