Crime scene investigation

Processing a crime scene is a critical aspect of forensic and police investigations. The initial actions taken at the site of a crime can be decisive for the success or failure of the subsequent resolution of the case. Through a detailed and enriched description, we will explore how first responders manage the crime scene, from their arrival to the collection and preservation of evidence.

Arrival at the scene of the crime

Initial assessment and scene control

When a crime is reported, the first officer to arrive—known as the first responder—must conduct a meticulous assessment of the situation. This process includes ensuring that the scene is safe for themselves and future investigators who arrive. The first responder is responsible for managing the situation, addressing immediate emergencies, and ensuring that the scene remains uncontaminated.

Emergency management

Any medical emergencies require immediate attention. If there are victims present, first aid must be administered, and it is vital to document any changes to the scene, such as the movement of objects or people, that may occur during the provision of aid.

Detention of witnesses and suspects

It is crucial for the officer to retain the individuals present at the scene. This may include witnesses and potential suspects. Keeping these people at the scene ensures that they can be interrogated to collect vital information without losing crucial details due to their premature departure.

Initial documentation

The first responder must take detailed notes of everything observed and performed. This initial documentation is fundamental to the progress of the investigation.

Preservation of the crime scene

Establishment of physical barriers

Creating a perimeter around the crime scene is one of the first steps to preserving the integrity of the evidence. Tapes, physical barriers, and the presence of officers are used to control access to the area.

Entry and exit log

A detailed record is maintained of all individuals who enter or exit the scene, including their arrival and departure times. This helps control who has had access to the scene and potentially could have altered it.

Protection against elements

In some cases, elements such as rain or wind can compromise the evidence. Methods like tents or cardboard covers may be used to protect certain areas and critical evidence.

Personal protective equipment

All individuals entering the scene must wear appropriate protective gear, such as suits, latex gloves, and shoe covers, to avoid contaminating the scene with their own DNA or other particles.

Processing of the crime scene

Systematic evidence search

The lead investigator assigns specific areas of the crime scene to different teams or individuals for a detailed and systematic search.

Search methods

Various search methods can be employed, including line, spiral, wheel, and zone searches, depending on the nature and size of the scene.

Detailed scene recording

Comprehensive documentation

Before altering any element, the crime scene must be fully documented. This includes taking photographs, making sketches, and recording videos, ensuring every detail as found is captured.

Evidence notes and records

Every piece of evidence collected is precisely documented, noting its exact location, who collected it, and when. This is vital for the chain of custody of the evidence.

Recovery and packaging of physical evidence

Collection methods

Depending on the nature of the evidence, specific collection methods are selected to prevent damage or loss of integrity.

Proper packaging

Proper packaging is essential to keep the evidence secure and unaltered until it reaches the forensic laboratory for analysis.


The role of the first responder is crucial in a crime investigation. Their ability to assess, protect, and document the scene adequately from the first moments can determine the success of resolving the case. This systematic approach not only preserves the integrity of the investigation but also maximizes the chances of achieving justice for the victims of the crime.

Elias, U., & Sienkiewicz-Charlish, A. (Eds.). (2014). Crime scenes: Modern crime fiction in an international context. Peter Lang AG.