Expertise in managing crime scenes is a crucial part of any investigation since the evidence gathered would paint a picture of what transpired for the judge and jury to evaluate (Brandl, 2018). To complete this image, we will use information gathered from the crime site, interviews with witnesses, pictures of the scene, physical evidence, and expert analysis of that evidence (Brandl, 2018). Note-taking, safeguarding a crime scene, evidence handling, and scaling the investigation to the event.

Several distinct procedures fall under the Tasks category of the STAIR Tool and are essential to preserving a crime scene in accordance with the standards of crime scene management. The investigator has specific responsibilities in locating, collecting, and safeguarding evidence so that it may be presented in court (Brandl, 2018). These activities involve shutting down the crime site, setting up perimeters, identifying a trail of contamination, and creating crime scene security. The officer who responds first to the site has an obligation to safeguard the public and the crime scene and manage the alterations made to the crime scene to the best of their abilities.

Upon arrival, the first responding officer or officers will conduct a crime scene assessment. They need to get there fast, but they need to be careful, keeping an eye out for potential witnesses, suspects, cars, and evidence (Brandl, 2018). It is crucial to a criminal investigation that the crime scene be thoroughly searched for tangible evidence. The success of a police investigation and subsequent prosecution hinges on the officer's ability to collect and adequately maintain tangible evidence that will stand up in court as proof of the crime (Brandl, 2018). In order for evidence to be acceptable in court and maintain its value for laboratory analysis, certain processes must be followed in its processing and preservation.

In crime scene one I said I would walk the room perimeter. A crime scene perimeter can be easily defined for locations with obvious obstacles, such as a structure with doors. It may be simple to define a crime scene perimeter when there are already obvious boundaries, such as in buildings with doors. It is evident that the crime scene has to be investigated methodically, and there are a variety of techniques to accomplish so. Everything must be located and labeled before it can be handled or gathered as evidence. When and where do you look for this proof, and how do you tally it? The strip technique, wheel method, spiral method, zone method, grid method, and line method are six of the most common crime scene search patterns employed by law enforcement organizations across the world (Brandl, 2018).

For the strip approach to be effective, crime scene investigators must travel a straight line from one side of the room or area to the other and then back again (Brandl, 2018). When searching a large area, a detective should walk clockwise around the outside to gradually approach the center. Someone doing laps in a swimming pool has a similar appearance. The crime scene is divided into smaller squares for more accessible analysis in the zone approach (Gehl & Plecas, 2016). A living room, for instance, can be subdivided into four equal areas, a different investigator can inspect each of which. Often, those squares are subdivided even further into smaller squares to help identify specific pieces of evidence.

Crime scene investigators rely heavily on the statements of first responders. The initial responding officer has several duties, including securing the crime scene, locating entry and exit points, and identifying any witnesses (Brandl, 2018).

The reason for sealing the evidence bags is one to preserve the item from contamination in an unprotected environment. Two, to prevent the item from contaminating other packaged evidence. Blood, hair, fiber, fingerprints, and other items subject to forensic investigation may be transferred from one location to another to show causality and establish causality in a geographic context (Gehl & Plecas, 2016). Other tangible evidence might build a timeline and provide circumstantial indicators of motivation, opportunity, or means. The investigation relies heavily on the physical evidence found at the crime scene. The two biggest threats to the integrity of physical evidence at a crime scene are the introduction of outside elements and the disruption of previously collected data (Gehl & Plecas, 2016).

If any tangible evidence is recovered, the chain of custody must begin at that time. Evidence obtained by Crime Scene Technicians will be recorded on a chain of custody inventory form (Gehl & Plecas, 2016). Evidence-collection officers will keep a log of all items they gather. The following details on the previous custodianship of the evidence will be included on the chain of custody inventory form for all specimens sent to a laboratory for analysis: name of the person who most recently had possession of the item; date, time, and mode of submission date, time, and method of reception at the laboratory; name and identification number of the person in the laboratory receiving the evidence (Gehl & Plecas, 2016).


Brandl, S. (2018). Criminal investigation (4th ed.). Thousand Oaks, CA: SAGE Publications. Chapter 5, “Physical Evidence and the Crime Scene Download Physical Evidence and the Crime Scene” (pp. 88–134 only) Criminal Investigation, 4th Edition by Brandl, S. Copyright 2018 by Sage Publications, Inc. Reprinted by permission of Sage Publications, Inc. via the Copyright Clearance Center.

Gehl, R. & Plecas, D. (2016) Introduction to Criminal Investigation: Processes, Practices and Thinking New Westminster, BC: Justice Institute of British Columbia Retrieved from

STUDENT REPLY #2 Yesica Liset Arevalo

In the crime scene 2, there is a gun and a laptop open. The gun is the key evidence as it was used to kill the man. Handling the weapon is important because it can lead to the killer. It is important to not tamper in any way with the gun because it can be disqualified as evidence. Making sure the gun is handled with gloves and put in an evidence bag is important to ensure the gun will be able to provide the evidence needed.

Securing the laptop can be important because it can hold information in regard to the crime scene. The tech lab can obtain more from the laptop than just leaving it there. The laptop can lead to reasoning of why the crime scene occur and it can help put pieces together and fill in the blanks of the crime scene, or it can obtain the motive of the murder.


Criminal Investigation, 4th Edition by Brandl, S. Copyright 2018 by Sage Publications, Inc. Reprinted by permission of Sage Publications, Inc. via the Copyright Clearance Center. Chapter 1. The investigation of a crime.