Crime Scene Investigation: Evidence Collection Procedures
This paper outlines the fundamental procedures a crime scene investigator follows when responding to a suspicious death involving potential sexual assault. Beginning with securing the scene and conducting a walk-through, the paper details the proper collection and packaging of biological evidence — including semen stains, blood samples, and human hair — as well as physical trace evidence such as cord fibers. Emphasis is placed on chain-of-custody integrity, proper packaging in paper (not plastic), labeling protocols, and time-sensitive handling of samples. The paper draws on forensic science guidelines to demonstrate a systematic, contamination-free approach to evidence collection.
- Securing the Crime Scene: Scene security, walk-through, and witness interview
- Collecting Biological and Semen Evidence: Locating and packaging semen stains from clothing
- Examining the Body and Blood Samples: Body examination, defensive wounds, and blood collection
- Hair Evidence Collection: Recovering and packaging hair samples from the victim
- Fiber and Cord Evidence: Collecting trace fibers from the cord around the neck
- Summary of Investigative Procedure: Recap of the full investigative sequence
✍️ How to write this paper — guide, tools & examples ▾
What makes this paper effective
- Follows a logical, step-by-step investigative sequence that mirrors real forensic protocols, making it easy to follow the procedural progression.
- Integrates direct quotations from forensic guidelines to ground procedural claims in authoritative sources.
- Consistently emphasizes contamination prevention and chain-of-custody integrity, reinforcing the core principle of forensic evidence handling.
- Applies general forensic principles directly to a concrete scenario, demonstrating applied rather than purely abstract knowledge.
Key academic technique demonstrated
The paper demonstrates applied procedural writing — translating technical forensic guidelines into a coherent, scenario-based narrative. Rather than simply listing rules, the writer situates each protocol within the context of a specific crime scene, showing how abstract guidelines translate into concrete investigative actions.
Structure breakdown
The paper opens by establishing scene security and the walk-through, then moves through successive categories of evidence: semen stains, blood, hair, and cord fibers. Each section follows a consistent pattern — identify the evidence type, explain its evidentiary value, then detail correct collection and packaging procedures. A brief conclusion synthesizes the investigative sequence. Two sources are cited throughout using a general reference style.
Securing the Crime Scene
When a jogger discovers the body of a woman who is naked from the waist down and apparently has a cord tied around her neck, the very first thing an investigator must do is secure the crime scene. Securing the scene allows for a walk-through — a careful search of the area for evidence without outside interference (Stuart, 2003). The crime scene must be thoroughly documented: any evidence found must be carefully identified and marked, and photographs and videos should be taken before the investigation proceeds. The investigator will also want to interview the jogger and check their background to determine whether the jogger may have been involved in the incident.
Collecting Biological and Semen Evidence
Because the woman was found without pants, sexual assault is a possible factor in this case. The detective will want to search for her clothing, and if the pants are located, they must be examined for semen stains. As forensic guidelines state, "Seminal stains are often, but not always, found on clothing, blankets, sheets. Allow any stains to air dry, wrap in paper, and package in paper bags. Do not use plastic bags" ("Evidence Collecting Guidelines").
It is critical that different samples are never mixed together. Each stain must be placed in a separate paper bag or envelope and marked with the appropriate information — including where and when it was collected and its position at the crime scene. Investigators should never attempt to wipe a dried stain from an object's surface with a moistened cloth or paper. Instead, they should wait until the stain has dried completely, then carefully scrape it off and place it in an envelope and paper bag.
Examining the Body and Blood Samples
The next step is to examine the body. If the woman was assaulted — sexually or otherwise — she may have defensive wounds on her body, as well as trace samples of the attacker's blood, hair, or skin on her body, hands, or fingernails.
When collecting blood samples from the scene, if blood has pooled it should be absorbed with sterile gauze or cotton, allowed to air dry at room temperature, and then refrigerated or frozen until delivered to the laboratory for analysis. This must be completed within the first 48 hours, or the samples may be rendered useless ("Evidence Collecting Guidelines"). Other blood samples — particularly dried blood — should be collected in clean paper, placed in a brown paper bag or box, and then sealed and labeled. If dried blood is present on the victim's clothing, pieces of the clothing should be removed and sealed separately. As with all evidence, each sample must be placed in sealed paper bags and labeled with the appropriate information.
References
"Evidence Collecting Guidelines." Crime Scene Investigator Network. Web. 17 June 2011. http://www.crime-scene-investigator.net/collect.html
James, Stuart, and Jon Nordby. Forensic Science: An Introduction to Scientific and Investigative Techniques. Boca Raton, FL: CRC, 2003. Print.
Create your account
Always verify citation format against your institution’s current style guide requirements.